5. Coronavirus disease (COVID-19)

Key information

Mode of transmission

Aerosolised droplets plus limited fomite transmission.

Incubation period

Most commonly 3–5 days (range 1–14 days).

Period of communicability

From 1–3 days before, and typically transmissibility peaks 5 days after symptom onset. Asymptomatic spread is documented.

Incidence and burden of disease

Global pandemic ongoing.

The burden of disease predominantly lies with older adults, those with comorbidities and health care workers exposed to patients with high viral loads. Children generally experience mild disease.

Funded vaccines

mRNA CV: Comirnaty (manufacturer: Pfizer/BioNTech).

Dose, presentation, route

  • 0.3 mL dose
  • multi-dose vial, to be diluted before use
  • intramuscular injection
  • latex free
  • Storage once thawed:
    undiluted, +2° to 8°C expiry 1 month (31 days)
    diluted, +2° to 30°C expiry six hours.

Funded vaccine indications and schedule

Two doses of mRNA-CV, given at least 6 weeks apart (minimum 21 days):

  • for use from age 12 years
  • given according to a prioritised schedule then to anyone aged from 12 years. 

Recommended, unfunded

Not available.

Contraindications A history of anaphylaxis to any component or previous dose of mRNA-CV is a contraindication.
Precautions

A definite history of anaphylaxis to any other product is a precaution not contraindication.

Defer second dose if individual develops myocarditis after first dose of mRNA-CV.

Potential responses to vaccine Generally mild or moderate: injection site pain, headache, fever, muscle aches, dizziness and nausea, a day or two after vaccination. These responses are more commonly reported after second dose and in younger adults (<55 years).

Vaccine effectiveness

Data from a phase III clinical trial showed efficacy against confirmed symptomatic COVID-19 to be 90–98% after two doses. Real-world data show similar effectiveness.

Public health measures

Ongoing rapid contact tracing and testing for all suspected cases and their close contacts. Quarantine and isolation of close contacts and cases until negative PCR result, if a close contact or a case is deemed recovered.

5.1. Virology

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is member of the Coronaviridae family and the Betacoronavirus genus. This enveloped, positive-strand RNA virus encodes four major structural proteins – spike (S), membrane (M), envelope (E) and a helical nucleocapsid (N). To enter host cells, the spike protein, which forms the characteristic crown-like (Latin: corona) surface structures, binds to the angiotensin-converting enzyme-2 (ACE2) receptor most frequently found on human respiratory tract epithelium.[1, 2]

The precise origin of this virus is unknown. First identified in humans in Wuhan, China, this virus shares a strong genetic sequence similarity to bat coronaviruses found in China,[3] and is a suspected zoonosis from bats via an intermediary animal, such as a pangolin.[4] As with most RNA viruses, mutations occur and variant strains of SARS-CoV-2 have been identified.

5.2. Clinical features

Coronavirus disease 2019 (COVID-19) is caused by the SARS-CoV-2 virus, which infects the respiratory tract and is transmitted human to human primarily through respiratory droplets. Documented transmission has also occurred through aerosols, direct contact and fomites (objects or materials that can carry infection) – though the latter is rare.

The reproduction number (R0) (see section 1.2.1) is estimated to be around 2–3.[5, 6] Transmissibility varies by setting, and recently identified variant strains of SARS-CoV-2 have been at the higher range of the estimated R0 values.[7, 8]

The symptoms of COVID-19 range widely from asymptomatic or a mild respiratory tract infection to severe and unusual ‘ground glass’ pneumonia, which can lead to severe inflammatory disease and respiratory failure. Classically, COVID-19 presents as respiratory symptoms with new or worsening dry cough, nasal congestion and fever. Unlike other respiratory viral infections, COVID-19 is frequently associated with a loss of taste and smell, and sometimes this is the only symptom. Some cases have reported gastrointestinal symptoms (diarrhoea), muscle aches, headache, ‘chills’, breathlessness and confusion. For around 80 percent of cases, COVID-19 is a mild disease, but some develop more severe disease, particularly older adults and those with comorbidities, which can progress to multi-organ and respiratory failure. As for influenza and other respiratory viruses, many of those with laboratory-confirmed infection remain asymptomatic.

In the early stages, it is difficult to distinguish COVID-19 from other common viral infections and, as of early 2021, the most reliable diagnostic test has been detection of viral mRNA from a nasopharyngeal swab, using PCR assay. Further methods of testing (such as saliva sampling) are under investigation. SARS-CoV-2 serology can help distinguish historic disease from mild current symptoms but is not in routine use.

The incubation period is typically around four to five days (range 48 hours–14 days). Individuals may be infectious up to three days before becoming symptomatic, with infectiousness typically peaking within five days of symptom onset.[9] High viral loads are detected in the nose at time of symptom onset.[10] Viable virus is not usually detectable for more than 10 days after symptom onset, although SARS-CoV-2 mRNA has been detected for up to 83 days in respiratory and stool samples.[9, 11] Unlike previous coronavirus outbreaks (SARS and MERS), transmission of SARS-CoV-2 can also occur before the onset of symptoms or from asymptomatic individuals.[12] Viral loads and infectiousness are highest immediately after symptom onset, and most transmission occurs in household settings.[13, 14]

It is currently unclear what protection previous infection with SARS-CoV-2 provides. A study in the UK in health care workers found protection against symptomatic COVID-19 to be similar to that reported for mRNA COVID-19 vaccine.[15] A previous history of SARS-CoV-2 infection was associated with an 83 percent lower risk of infection, with a median time to re-infection of over five months.[16] Only about one third of the reinfections in health care workers presented as typical COVID-19 symptoms, as compared with 78 percent of new infections.[15] Neutralising antibodies have been detected for at least eight months after primary infection, even without natural boosting as in New Zealand.[17]

5.2.1. Children and young adults

In younger people, particularly infants and children under 10 years old, infection is often asymptomatic or mildly symptomatic. Those aged under 20 years appear to have a lower susceptibility than adults and are much less likely to develop severe infection requiring hospitalisation.[18] However, as seen in adults, in the UK children and young people (up to age 17 years) at increased risk for paediatric intensive care admission due to COVID-19 were more likely to have pre-existing conditions (including asthma, diabetes and Down syndrome) and highest for those with multiple medical problems, with similar but greater risk patterns as for influenza.[19] Current evidence suggests that preschool and young school-age children are much less significant in transmitting the disease than has been documented for influenza. In contrast, asymptomatic older school-age children, adolescents and young adults are highly effective transmitters of SARS-CoV-2.[20] However, the role children play in transmitting SARS-CoV-2 is still unclear and could change as new variants evolve. Notably, in household settings, secondary attack rates have been found to be higher when the index case has been a child.[21]

5.2.2. Risk groups

Risk factors for severe disease include older age, male, smoking,[22] obesity and chronic medical conditions, including type 2 diabetes mellitus, cancer, chronic respiratory disease, cardiovascular disease, chronic kidney disease, hypertension and being immunocompromised.[23] Increased incidence is well documented in some ethnic groups but seems primarily related to prevalence of the risk factors listed above. Increasing age is the most important risk factor for severe disease, due to declining immune function and high prevalence of comorbidities. The highest rates of mortality are in the oldest age groups, especially those aged over 80 years (at a rate 20-fold higher than for those aged 50–59 years in the United Kingdom).[23]

Health care workers

Patient-facing health care workers caring for patients with COVID‑19 are likely to be exposed to higher viral loads, placing them and their household members at greater risk of developing COVID‑19 than the general population.[24] In Scotland, one-sixth of the COVID‑19 cases admitted to hospital were health care workers and their household members.[24] Health care workers have also been implicated in the spread of SARS‑CoV‑2 within health and long-term care facilities.[24, 25, 26] However, the use of personal protective equipment (PPE) and other measures aimed at reducing nosocomial viral transmission have been shown to be effective, such that, where COVID‑19 is prevalent in the community, health care workers are more likely to catch COVID‑19 from an infected household member.[14]

Pregnant women

Although pregnant women are not at increased risk of SARS-CoV-2 infection, they are at increased risk of severe disease and death compared with age-matched non-pregnant women.[27, 28] While the absolute risk of severe outcomes among pregnant women is low compared with absolute risk due to advanced age, the rate of ICU care for COVID‑19 has been found to be three-fold higher (adjusted risk ratio 3.0; 95% CI 2.6-3.4) for pregnant women than for non-pregnant women,[29] and the case-fatality rate in one United States study was 13.6-fold higher for pregnant women.[28] Obesity, hypertension, asthma, autoimmune disease, diabetes and older age are also associated with severe COVID‑19 in pregnant women.[30]

Infants of mothers with COVID‑19 are at increased risk of preterm birth and neonatal ICU admission.[30] Early studies do not suggest intrauterine transmission, but transmission during birth has been shown in around 3 percent of neonates, predominantly from asymptomatic or mildly symptomatic mothers.[31] Most neonatal infections are asymptomatic or mild, but around 12 percent experience severe disease with dyspnoea and fever as the most commonly reported signs.[32]

5.2.3. Post-infection complications

Longer lasting effects of infection have been reported, described as ‘long-COVID’. Long-COVID appears to affect around 10 percent of those infected, particularly those with at least five symptoms in the first week of illness.[33, 34, 35] Post-acute manifestations include cardiovascular, pulmonary and neurological effects, including chronic fatigue, dyspnoea, specific organ dysfunction and depression.[36] Paediatric multisystem inflammatory syndrome (PIMS-TS or MIS-C) has been temporally and rarely associated with largely asymptomatic SARS-CoV-2 infection in children and adolescents.[37, 38]

5.2.4. SARS-CoV-2 variants

As with all viruses, new variants have evolved. Most recently, certain variants have been shown to bind the ACE2 receptor more readily, making the variants more transmissible. It is unclear whether these variants result in more cases of severe disease, but irrespectively, the greater numbers of people becoming infected is increasing the burden of the disease.[7, 8] There is evidence from the UK (in preprint) that recent variants (eg, Delta) are more transmissible than the former strains.[39] The CDC has classified genetic variants into three classes:[40]

  • Variants of interest – specific genetic markers that are predicted to affect transmission, diagnostics, therapeutics or immune escape (for example, reduced antibody neutralisation).
  • Variants of concern – evidence of increased transmissibility, more severe disease, reduction in antibody neutralisation, reduced vaccine or treatment efficacy or diagnostic detection failures.
  • Variants of high consequence – clear evidence that prevention measures or medical countermeasures have significantly reduced effectiveness.

5.3. Epidemiology

5.3.1. Global burden of disease

Clusters of distinctive pneumonia cases were observed in Wuhan, China during December 2019. The cause was identified in January 2020 as a novel coronavirus that had genetic and clinical similarity to the coronavirus causing the severe acute respiratory syndrome (SARS) epidemic from 2002 to 2004. Consequently, the novel coronavirus was named SARS-CoV-2 and the associated disease named Coronavirus Disease 2019 (COVID‑19). Due to the rapid spread, a public health emergency of international concern (PHEIC) was announced in late January 2020. By the time the COVID‑19 pandemic was declared by the World Health Organization (WHO) on 11 March 2020, there were 118,000 reported COVID‑19 cases and 4,291 associated deaths in 114 countries. The global death toll surpassed 1 million by late September 2020.

Almost a year later (as of 8 August 2021), over 4.2 million deaths and over 200 million confirmed cases were reported to the WHO, around 3 million new cases per week continue to be reported. The Americas, Europe and South-East Asia had the highest numbers of recorded cases (78 million in the Americas and 60 million in Europe, South-East Asia 39 million cases; 4.8 million cases reported in the Western Pacific region).

See the WHO Coronavirus Disease (COVID‑19) Dashboard for the latest official data. Actual rates are expected to be considerably higher than officially reported rates.

The infection-fatality rate, while still high particularly in the older age groups, has reduced since the start of the pandemic, with improved clinical recognition and management and the use of therapies of demonstrated value, such as dexamethasone (see Figure ‎5.1.).[41, 42]

Figure 5.1: Total confirmed COVID-19 deaths and cases per million people, World (as of 5 August 2021)
Note: The confirmed counts shown here are lower than the total counts. The main reason for this is limited testing and challenges in the attribution of the cause of death.

Graph that shows the rise in confirmed cases to over 25,000 per million people at the start of August 2021. The total confirmed deaths was almost 550 per million at the start August 2021.

Sources: Center for Systems Science and Engineering (CSSE) Johns Hopkins University of Medicine; Our World in Data

The use of vaccines is anticipated to reduce the global burden of COVID‑19 significantly. The first phase I clinical trial for a COVID‑19 vaccine commenced in March 2020. The first public vaccination dose was given as part of a mass campaign in the United Kingdom on 8 December 2020. By 31 January 2021, almost 100 million COVID‑19 vaccine doses had been given worldwide, predominantly in high income countries. As of 11 August 2021, that had increased to over 4.4 billion doses with over 865 million people fully vaccinated. 

See the WHO Coronavirus Disease (COVID‑19) Dashboard and the Our World in Data website for the latest official data.

5.3.2. New Zealand epidemiology

As of 6 August 2021, New Zealand had 2,524 cases and 26 deaths associated with COVID 19 notified since 24 February 2020. Most cases were observed in those aged 20–34 years (1059 cases, 37%), 35–49 years (638, 22%) and 50–64 years (536, 19%). This reflects the age groups most likely to be travelling to New Zealand and the proportion of cases arriving at the border being detected in managed quarantine facilities. In children, there were 310 cases (11%) aged 5–19 years and 85 cases (3%) aged under 4 years. To date, no child under 13 years of age has been hospitalised with COVID 19 in New Zealand.

Currently, most of the cases occur in managed facilities (over 95 percent from 1 January to 9 August 2021). As shown in Figure ‎5.2, since the first case was reported in 2020 to 1 February 2021, 60 percent of total confirmed cases had been imported, 17 percent were related to an imported case and 20 percent were locally acquired from a known case and 3 percent were locally acquired from an unknown source. According to the Ministry of Health, a total of 2,525,687 tests were conducted from 22 January 2020 (the date of the first test in New Zealand) to 9 August 2021. Of these, 2158 tests (0.1 percent) in the community and 1492 tests (0.4 percent) in managed facilities were positive for SARS-CoV-2.

Figure 5.2: Pooled weekly confirmed COVID 19 cases by source, 24 February 2020 to 8 August 2021

This graph shows that the case numbers peaked before May 2020, including imported, import-related and locally acquired cases. Since then most cases have been imported, with a few import-related cases, and a set of locally acquired cases in August/September 2020 and February 2021.

Source: ESR

For the current case status, see the NZ COVID‑19 Dashboard produced by the Institute of Environmental Science and Research (ESR), and for further information about current sources of cases, see COVID-19: Source of cases on the Ministry of Health website.

Strategy for prevention

The first case of COVID‑19 was reported in New Zealand on 28 February 2020. During March, cases numbers increased, and clusters of transmission were identified. Border restrictions were implemented on 16 March 2020. On 25 March 2020, New Zealand entered a nationwide lockdown (alert level 4).

New Zealand implemented an elimination strategy with four defined levels of pandemic response to prevent the spread of SAR-CoV-2. A mobile phone app aided rapid contact tracing. For further information about the country’s alert system levels, see the Unite Against COVID-19 website.

These strategies were effective in containing the spread of SARS-CoV-2 in New Zealand (see case curve for 24 February to 8 June 2020 at NZ COVID‑19 Dashboard for details). These restrictions were able to rapidly stop the spread of the virus within the country. Only 19 percent of the introductions of virus resulted in ongoing transmission or more than one additional case.[5]

 5.4. Vaccines

5.4.1. Introduction

Clinical trials for COVID‑19 vaccine candidates began shortly after the pandemic was announced in March 2020. The New Zealand Government signed advanced purchase agreements for four vaccine candidates, with purchase dependent on approval for use from the New Zealand Medicines and Medical Devices Safety Authority (Medsafe). This is an ongoing process and, therefore, the availability and eligibility for these different vaccines may change.

5.4.2. Available vaccines

Vaccines for COVID 19 continue to undergo phase III clinical trials, and the Medsafe review process is ongoing for each vaccine candidate. Provisional approval was granted for use of New Zealand’s first COVID 19 vaccine on 3 February 2021, namely, a mRNA-based COVID 19 vaccine (mRNA-CV, trade name Comirnaty) manufactured by Pfizer/BioNTech. In addition, two adenoviral vector COVID-19 vaccines were also granted provisional approval in July 2021: COVID-19 Vaccine Janssen and COVID-19 Vaccine AstraZeneca; the role these will play in the New Zealand COVID-19 vaccination programme is still to be confirmed.

Funded vaccines

The mRNA-CV consists of messenger ribonucleic acid (mRNA) encoding the full-length spike glycoprotein of the SARS-CoV-2 virus inside a lipid nanoparticle. The spike protein has an adjuvant effect, so no additional adjuvant is included. It is designated BNT162b2 in clinical trials conducted by Pfizer and BioNTech.

mRNA-CV (Comirnaty, Pfizer/BioNtech)

Each 0.3 mL dose of mRNA-CV contains:

  • 30 µg of single-stranded 5’-capped mRNA encoding pre-fusion stabilised SARS-CoV-2 full-length spike glycoprotein embedded in a lipid nanoparticle. The mRNA is produced using cell-free in vitro transcription from DNA templates.
  • The lipid nanoparticle contains ALC-0315 (4 hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)), ALC 0159 (2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamid), distearoylphosphatidylcholine (DSPC)) and cholesterol. As well as buffers, mRNA-CV contains sucrose to protect the lipid during ultra-low temperature storage.

This mRNA vaccine delivers the instructions for human cells to build the viral antigen, SARS-CoV-2 spike protein. The mRNA is temporarily protected from degradation by the lipid nanoparticle that also facilitates fusion with the recipient’s cell wall.[43, 44]

Other vaccines

An adenoviral vector COVID-19 vaccine (Ad26.COV2.S, brand name COVID-19 vaccine Janssen; manufactured by a subsidiary of Johnson and Johnson) was approved for use in New Zealand on 7 July 2021. This vaccine (abbreviated here to Ad26-CV) contains a modified non-replicating human adenovirus, Ad26, which has a transgene inserted into its genome that codes for the COVID-19 prefusion SARS-CoV-2 spike protein. The adenovirus delivers the instructions to make SARS-CoV-2 viral protein – it has been modified to be unable to replicate so only the antigen, the spike protein, is produced. 

Another adenoviral vector COVID-19 vaccine (COVID-19 vaccine AstraZeneca) was provisionally approved for use in New Zealand on 29 July 2021. Using a similar platform to Ad26-CV, this vaccine (abbreviation ChAd-CV) contains a recombinant non-replicating chimpanzee adenovirus, ChAdOx1, encoding the prefusion SARS-CoV-2 spike glycoprotein.

5.4.3. Efficacy and effectiveness

mRNA COVID-19 vaccine – Comirnaty (Pfizer/BioNTech)

Immunogenicity

Assessing immunogenicity was a key component of the early-phase clinical trials of COVID‑19 vaccines before the phase III efficacy studies were conducted. Virus neutralising antibody responses measured the killing of live SARS-CoV-2 and/or pseudo-virus in cell culture. Since no correlates of protection have yet been established, humoral responses were compared with human convalescent sera collected from patients who had recovered from COVID‑19.

Two vaccine candidates were evaluated (BNT162b1 and BNT162b2) in the initial phase I and II clinical trials. Both demonstrated similar dose-dependent neutralising antibody titres, which were similar or higher to the titres in convalescent sera.[45] Anti-receptor binding domain (anti-RBD) IgG antibodies also increased with dose.[46] As seen for other vaccines, the antibody response was lower in older people (aged 55–85 years) than in younger people (aged 18–55 years), but both groups had higher average neutralising antibody levels than those with prior SARS-CoV-2 infection.

The immunogenicity of mRNA-CV in adolescents aged 12–15 years was non-inferior to those aged 16–25 years in a phase III clinical trial. The neutralising antibody response in 190 adolescents was higher than in 170 young adults (geometric mean ratio 1.76; 95% CI 1.47-2.10).[47]

Efficacy – clinical trial data

Efficacy of mRNA-CV (BNT162b2) was assessed in the phase III component of a large clinical trial in which 43,448 participants aged 16–85 years in Argentina, Brazil, Germany, Turkey, South Africa and the United States were randomised to receive vaccine or saline placebo.[48] Two doses were given 21 days apart. According to interim data, vaccine efficacy (VE) against symptomatic PCR-confirmed COVID‑19 was 94.8 percent (95% CI: 89.8–97.6%); eight cases in the vaccinated group and 162 cases in control group developed COVID‑19 at least seven days after dose two. Evidence of previous SARS-CoV-2 infection did not alter this efficacy (VE 95.0% without and 94.6% including those with previous infection). Similar efficacy (90–100 percent) was observed across all subgroups as defined by age, sex, race, ethnicity, baseline body-mass index (35% of participants were obese, BMI ≥ 30) and the presence of at least one co-existing medical conditions (in 21%). Moderate early protection against COVID‑19 was observed before the second dose.[48] This clinical trial is ongoing, and further data is anticipated as predefined endpoints are reached. The trial is due to be completed in January 2023.

The observed vaccine efficacy for mRNA-CV in adolescents aged 12–15 years during a phase III clinical trial was 100 percent (95% CI 75.3–100) against symptomatic COVID-19. A total of 2,220 randomised participants received two doses of vaccine or saline placebo given 21 days (19-42 days apart. No cases of severe COVID-19 were observed in this age group.[47]

Effectiveness – real-world experience

Early data from Israel at the start of its national COVID-19 immunisation programme, which included around 1.2 million vaccinated and unvaccinated individuals aged from 16 years, demonstrated that mRNA-CV was highly effective at preventing COVID-19 and severe disease, and these data were in line with those observed during clinical trials.[49] See Table 5.1 for comparison.

In the UK, a single dose of mRNA-CV was associated with a significant reduction in symptomatic COVID-19 cases in older adults (aged from 70 years) for at least 6 weeks. Vaccine effectiveness was observed from 10–13 days after vaccinations, by days 28–34 vaccine effectiveness reached 70 percent (95% CI 59–78 percent), then plateauing to 61 percent (51–59 percent). Additionally, those that had been vaccinated were 43 percent (33–52 percent) less likely to require emergency hospitalisation and at 51 percent (37–62 percent) lower risk of death. A second dose (given 12 weeks after dose one) provided further protection against symptomatic disease (at day 14, vaccine effectiveness reached 89 percent [85–93 percent).[50]

Table 5.1: Comparison of clinical trial and real-life vaccine effectiveness following two-dose vaccination with mRNA-CV

Two-doses of mRNA-CV (Comirnaty) given 21 days apart

Clinical trial efficacy
compared with placebo control

Real-life effectiveness
compared with unvaccinated individuals

 

VE %

95% CI

VE %

95% CI

Documented SARS-CoV-2 infection

 

 

92

88–95

Symptomatic COVID-19

95

90–98

94

87–98

Hospitalised for COVID-19

 

 

87

55–100

Severe disease

95

90–98

92

75–100

Death associated with COVID-19

 

 

92

88–95

Effectiveness against transmission

Effectiveness of mRNA-CV against transmission of SARS-CoV-2 is unclear. It is expected that, at the least, with fewer symptomatic people coughing and producing large quantities of virus, the spread of the virus will decrease, and evidence is emerging that mRNA-CV can protect against viral infection as well as symptoms. Interim data published by the CDC in the United States showed vaccine effectiveness against SARS-CoV-2 infection (regardless of symptoms) for both mRNA COVID vaccines (Comirnaty and the Moderna vaccine) to be 80 percent (95% CI 62–91) from 14 days after dose 1 and 90 percent (68–97) at least 14 days after dose 2 amongst health care, emergency and frontline staff without previous SARS-CoV-2 infection.[51] Evidence (non-peer reviewed) from the UK has also demonstrated that transmission within a household was reduced by approximately half when the index case was vaccinated with mRNA-CV.[52]

Efficacy against new virulent SARS-CoV-2 strains

Currently there is limited clinical data about the efficacy of mRNA-CV against some emerging variants of SARS-CoV-2 strains (variants of concern), evidence is emerging of increased transmissibility and reduced neutralisation from convalescent and post-vaccination serum antibodies.[40] In vitro study data has shown that sera from vaccine recipients are able to neutralise a pseudo-virus bearing variant spike proteins from the United Kingdom strain but are slightly less effective against the South African strain. It is anticipated that small differences in viral neutralisation are unlikely to lead to significant reduction in vaccine effectiveness against the latter variant.[53]

Duration of immunity

There has been insufficient time since the commencement of clinical trials and vaccination campaigns to assess how long immunity lasts following immunisation or natural infection. It is unknown whether booster vaccinations will be required to maintain immunity.

5.4.4. Transport, storage and handling

mRNA COVID-19 vaccine – Comirnaty (Pfizer/BioNTech)

To preserve the integrity of the mRNA in this vaccine, storage at ultra-low temperature freezer (between -90°C and -60°C) is required. At these ultra-low temperatures, the shelf-life is six months. Trays of unopened vials may be stored and transported at -25°C to -15°C for a total of 2 weeks on one occasion only. Once an individual vial has been removed from the vial tray, it should be thawed for use.

The vaccine will be thawed in batches, packed into cartons and distributed from the central warehouse. Each carton will have a label with an updated batch number and expiry date and time. Expiry reduces from 6 months to 31 days once thawed. 

Thawed vaccines will be shipped to vaccination sites as per the standard cold chain distribution process.

Store undiluted vials at +2°C to +8°C for up to 31 days (including up to 12 hours for transportation) or up to two hours at room temperature (up to +30°C). After dilution, store vials between +2°C and +30°C and use within six hours. Any remaining vaccine in the vial must be discarded after six hours. Do not refreeze. See 2021 Addendum to the National Standards for Vaccine Storage and Transportation for Immunisation Providers 2017 (2nd edition).

5.4.5. Dosage and administration

mRNA COVID 19 vaccine – Comirnaty (Pfizer/BioNTech)

Each dose of mRNA-CV is 0.3 mL (30 µg) to be administered intramuscularly. Two doses are given at least 6 weeks (a minimum of 21 days) apart for individuals aged 12 years or older.

Each multi-dose vial contains 0.45 mL of vaccine and should be diluted with 1.8 mL of 0.9% NaCl. Once diluted, each reconstituted vaccine will supply six (up to seven) doses of 0.3 mL. If the amount of vaccine remaining in the vial cannot provide a full 0.3 mL dose, discard the vial and any excess volume. Do not pool excess vaccine from multiple vials.

An observation period following vaccination of at least 15 minutes is recommended (see section ‎5.6.2). This is to ensure that any anaphylactic-type reactions can receive prompt treatment.

This vaccine is latex-free. The vial stopper is made with synthetic rubber (bromobutyl), not natural rubber latex.

Preparing mRNA-CV multi-dose vial

Note that the process for drawing up mRNA-CV differs from the recommendations for other multi-dose vial vaccines as described in section ‎A7.2 in ‎Appendix 7. To follow international guidance around the use of low dead space needles, the needle used to draw up mRNA-CV is also used to administer the injection. Unless you plan to administer the vaccine dose immediately, carefully replace the needle guard and place syringe onto a ridged tray for storage, for example, if all five or six doses are prepared at one go in a mass vaccination setting.

For detailed instructions for mRNA-CV multi-dose vial preparation and administration see the most current IMAC COVID-19 education factsheet ‘Instructions for multi-dose vial Pfizer/BioNTech vaccine: preparation and administration’ available from the IMAC COVID-19 Education website.

5.5. Recommended immunisation schedule

5.5.1. Recommended and funded

The COVID-19 vaccines will only be available according to a prioritisation schedule for defined groups (see COVID-19: When you can get a vaccine on the Ministry of Health website).

mRNA COVID 19 vaccine – Comirnaty (Pfizer/BioNTech)

All individuals from the age of 12 years are recommended to receive two doses of mRNA-CV given at least 6 weeks (42 days) after the first dose. For individuals requiring earlier full protection, for example, those at high risk of exposure to SARS-CoV-2 (such as border staff or overseas travellers) or prior to planned immunosuppression (see section 5.5.7), can continue to have the second dose at least 21 days after the first. 

The safety and efficacy of mRNA-CV has not yet been established for use in those aged younger than 12 years. A clinical trial is ongoing in younger age groups.

This vaccine will not be available to purchase, for example, for those wishing to travel overseas before the individual’s prioritised group rollout. It is possible to apply for an early mRNA-CV vaccination to travel overseas on compassionate grounds or for reasons of national significance, as defined at COVID-19: Applying for an early vaccine for travel overseas on the Ministry of Health website.

5.5.2. Spacing of COVID-19 vaccination and other vaccines

In view of the absence of data on concomitant delivery, and to minimise confusion with any associated reactions, a gap of two weeks is generally recommended before giving mRNA-CV after any other vaccine. However, based on first principles of how these vaccines work, adverse impacts on immunogenicity or safety are unlikely with a shorter gap, so if it is clinically important to deliver in a shorter time, do not delay.

  • If it is not practicable to keep a two-week gap between vaccines, then do not delay.
  • If a live vaccine has been administered, wait four weeks before giving mRNA-CV but if not practicable, then do not delay.
  • Otherwise, if a COVID-19 vaccine is administered first, the general advice is to maintain a two-week gap before any other vaccines.

5.5.3. Previous history of COVID-19 infection

Vaccination should be offered regardless of an individual’s history of symptomatic or asymptomatic SARS-CoV-2 infection. As the duration of protection post infection is currently unknown, vaccination is recommended. There are no safety concerns around giving mRNA-CV to individuals with a history of SARS-CoV-2 infection or symptomatic COVID-19. Viral or serological testing is not required before vaccination.

In a person who has had a previous SARS-CoV-2 infection, an individual is considered fully immunised only after two doses of mRNA-CV (or another COVID-19 vaccine, see section 5.5.4) given at least 42 days apart. In these individuals, vaccination is recommended to be given from 4 weeks after recovery, or from the first confirmed positive PCR test if asymptomatic, and when cleared to leave isolation by a clinician.

5.5.4. Previous COVID-19 vaccination

Individuals who have had one dose of mRNA-CV should receive a second dose of the same mRNA-CV to complete the vaccination course. Since there is currently no maximum duration between doses one and two of mRNA-CV, it is not indicated to restart the course or to give a third dose.

Data is limited on the interchangeability between COVID‑19 vaccines. Other vaccines should not be substituted to complete the course, where possible.

Based on first principles, a dose of a different vaccine is likely to adequately boost immunity since all the current COVID-19 vaccines target the same antigen, namely SARS-CoV-2 spike protein. In cases where one dose of any COVID-19 vaccine (including Janssen vaccine) has been given outside of New Zealand, one dose of mRNA-CV is recommended at least 4 weeks after the first vaccine dose. For those who have received two doses of Sinopharm or Sinovac overseas, a further dose of mRNA-CV is recommended.

5.5.5. Breastfeeding

While lactating women/people were not included in phase III studies, as with all schedule vaccines, there are no safety concerns about giving mRNA-CV to lactating women/people.

5.5.6. Pregnancy

Women/people who are pregnant are encouraged to be routinely vaccinated with the mRNA-CV at any stage of pregnancy. The risk of an adverse outcomes from COVID-19 infection during pregnancy is significantly higher compared to non-pregnant adults (see section ‎5.2.2).[30] Internationally, many women have been given this vaccine while pregnant and safety surveillance data of large numbers of pregnant people indicate that there are no safety concerns with administering mRNA-CV in any stage of pregnancy.[54] There is also emerging evidence of antibody transfer in cord blood and breast milk which can offer protection to infants through passive immunity.[55, 56, 57]

Pregnant women/people with questions or concerns are encouraged to discuss them with their health professional. People who are trying to become pregnant do not need to avoid pregnancy after receiving mRNA-CV.

5.5.7. Individuals receiving immunosuppressive agents

There are no safety concerns around administering mRNA-CV to individuals who are receiving immunosuppressive agents. As with other non-live vaccines, the antibody response to mRNA-CV may be reduced and protection may be suboptimal but, it is likely to be adequate to protect against severe disease.

It is recommended to discuss the optimal timing for vaccination with a specialist before the vaccine appointment for those who are severely immunocompromised. Ideally, vaccination should be conducted prior to any planned immunosuppression (see section ‎4.3.7). In this case, the two doses are recommended to be given at least 21 days apart prior to commencement of treatment. For those who have already commenced or completed immunosuppressive treatment, give two doses at least 6 weeks apart.

Close contacts of immunocompromised individuals are recommended to receive mRNA-CV when available to widen protection.

5.5.8. Frail elderly individuals

In general, it is recommended that all eligible adults, including the frail and elderly with comorbidities are offered vaccination against COVID-19, if there are no contraindications (see section 5.6.1) to its administration, to provide protection for the individual as well as their community.

The Ministry of Health Guidance Statement states (as of 7 July 2021):

As with all clinical interventions, there needs to be an individual risk/benefit appraisal and shared decision making between clients, whanau, surrogate decision makers, and clinicians on the individual and collective benefits and risk of COVID-19 vaccination. For frail elderly people with a prognosis of a short number of weeks (including those in terminal decline or on an end-of-life care pathway) the individual risk/benefit appraisal will be particularly important.

See Clinical guidance and resources on the Ministry of Health website.

5.5.9. Individuals receiving cardiology care

In general, it is recommended that all people aged 12–29 years receive two doses of mRNA-CV given 6 weeks apart. Pre-existing cardiac conditions, in general, are not regarded as precautions to vaccination. This includes pre-existing rheumatic heart disease. Note that many cardiac conditions increase the risk from COVID-19 disease.

5.6. Contraindications and precautions

See also section ‎2.1.3 for pre-vaccination screening guidelines and section ‎2.1.4 for general contraindications for all vaccines.

5.6.1. Contraindications

A history of anaphylaxis to any component or previous dose of mRNA-CV is a contraindication.

5.6.2. Precautions

A definite history of immediate allergic reaction to any other product is considered as a precaution but not a contraindication to vaccination with mRNA-CV. A slightly increased risk of a severe allergic response in individuals who have had a previous anaphylaxis-type reaction needs to be balanced against the risk of SARS-CoV-2 exposure and severe COVID‑19. These individuals can still receive mRNA-CV and observation extended to 30 minutes after vaccination in health care settings, where anaphylaxis can be immediately treated with adrenaline.

When vaccinating an elderly person who has an intercurrent or comorbid condition, ensure they are stabilised or as well as possible before they have the vaccine. Following vaccination ensure good hydration and careful management of potential systemic adverse events, such as fever. It is advisable for them to be with someone else for 24 hours after receipt of the vaccine to help manage potential adverse events.

Defer the second dose if myocarditis occurs after the first dose of mRNA-CV. Seek further advice from IMAC.

5.7. Potential responses and AEFIs

5.7.1. Potential responses

Commonly reported responses to mRNA-CV (during clinical trials and post-licensure) are injection-site pain, headache and fatigue; other responses included muscle aches, feeling generally unwell, chills, fever, joint pain and nausea. These occurred most often after dose two and in younger adults (aged 18–55 years), and within one or two days of vaccination. Most are mild or moderate in severity and are self-limiting.[48, 58] Analgesia, such as paracetamol or ibuprofen, can be taken for pain and discomfort following vaccination.

Breast screening and CT scans

Transient unilateral axillary adenopathy, a known response to vaccination, is particularly noted following vaccination with mRNA-CV due to the scale of the roll-out and age groups being immunised. Early estimates suggest that 12–16 percent of vaccine recipients experience axillary adenopathy after vaccination with mRNA-CV, starting one or two days after vaccination and which can persist for at least two weeks.[59]

When attending breast screening and mammography appointments, it is recommended that individuals advise the radiographer or doctor that they have received a COVID-19 vaccine recently. It is advised to monitor any lymph node changes that persist for longer than 6 weeks after vaccination.[59]

Likewise, individuals undergoing FDG PET/CT scans for cancer screening are advised to inform the radiologist or their oncologist that they have been recently vaccinated, or, if possible, to have mRNA-CV at least 2 weeks before a scheduled scan or as soon as possible afterwards. Treatment should not be delayed.

5.7.2. AEFIs

Adverse events following immunisation (AEFIs) with mRNA-CV are being closely monitored during clinical trials and post marketing surveillance. A dedicated COVID-19 vaccine AEFI reporting tool is available online from CARM (see section 1.6.3). Medsafe reports weekly on the AEFI reported to CARM after mRNA-CV vaccinations (see the Medsafe website).

A list of adverse events of special interest (AESI), including those previously associated with immunisation in general and with the particular vaccine platforms, has been created by Safety Platform for Emergency Vaccines (SPEAC) in collaboration with the Coalition for Epidemic Preparedness Innovations (CEPI) and based on existing and new Brighton Collaboration case definitions. For further information, see the Brighton Collaboration website. Global pharmacovigilance and active safety monitoring systems continue to watch for both AESI and unexpected AEFI. As of 16 January 2021, no AESI signals had been detected up to 21 days after vaccination by the Vaccine Adverse Event Reporting System (VAERS) in the US, following the administration of 121,000 doses of mRNA-CV (Comirnaty).[58]

Preliminary phase II/III clinical trial safety data reported lymphadenopathy in 64 (0.3%) vaccine recipients and six (<0.1%) placebo recipients (follow-up of up to 14 weeks after second dose of a subset of 18,860 participants who received at least one dose of mRNA-CV). Four vaccine-related adverse events were recorded (namely, shoulder injury related to vaccine administration, lymphadenopathy local to injection site, paroxysmal ventricular arrhythmia and right leg paraesthesia). No deaths were related to either the vaccine or the placebo.[48] During clinical trial follow-up to 1 February 2021, acute peripheral facial paralysis (Bell’s palsy) was reported by four vaccinated participants and none in the placebo group.[60] No safety signal has been detected for this condition as an AESI, and clinical trial safety monitoring is ongoing.

Myocarditis and pericarditis

A very small increase in incidence of myocarditis and pericarditis has been observed following the second dose of mRNA-CV vaccination (40.6 cases per million doses in young males and 4.2 cases per million in young females, aged 12-29 years, decreasing to 2.4 and 1.0 per million, respectively, in men and women aged over 30 years).[61] Most cases occur within 14 days of vaccination. A review of clinical records in the US observed the median time to onset for myocarditis was 3.5 days (interquartile range 3.0–10.8 days) after vaccination and a median of 20 days (6.0–41 days) for pericarditis.[62] These cases have typically been mild with full recovery after standard treatment and rest.

Myocarditis and pericarditis are uncommon conditions considered to be associated with viral infection, including COVID-19. Recently vaccinated individuals should seek immediate medical attention if they experience new onset of (acute and persisting) chest pain, shortness of breath or arrhythmia (palpitations). Diagnosis is based on elevated troponin, C-reactive protein and electrocardiogram and/or MRI findings. Report all cases to CARM as Medsafe continues to monitor this AEFI closely. Defer the second dose if myocarditis occurs after the first dose of mRNA-CV and seek advice from IMAC.

Anaphylaxis

Following approval for use in the US, the VAERS detected 50 cases of anaphylaxis after administration of 9,943,247 doses (five cases per million doses) mRNA-CV (Pfizer/BioNTech). The median interval to symptom onset was 10 minutes (range <1–150 minutes), 90 percent occurred within 30 minutes of vaccination.[58] All were successfully treated with adrenaline. See section ‎5.6 for contraindications and precautions.

Frail elderly

A follow-up, after approximately 2 million doses of mRNA-CV were delivered through long-term residential care facilities to elderly and frail residents in the US found no increase in deaths post vaccination.[43] Deaths were to be expected and consistent with the all-cause mortality rate and causes of death for these individuals, who have multiple comorbidities, declining health and require end-of-life care.[43] There are no added safety concerns about the use of this vaccine in the elderly.[58, 63]

5.8. Public health measures

There is an ongoing COVID‑19 pandemic globally. New Zealand has implemented strict pandemic response control measures to prevent the spread of SARS-CoV-2 in the community. New Zealand has a four-level alert system to stipulate the measures that the whole population needs to take (as described on the Unite Against COVID-19 website).

All individuals with symptoms of COVID‑19 are expected to seek medical advice and be tested for infection. Rapid contract tracing and nasopharyngeal testing continue to be fundamental components of the public health measures.

Immunisation using COVID‑19 vaccines is part of the public health strategy aimed at reducing the risk of transmission of SARS-CoV-2 in the community to below an R0 of 1 and to reduce the severity of disease and minimise the burden on the health care system in the event of a community outbreak. The initial phases of the vaccination programme are aimed at protecting those at risk of exposure to SARS-CoV-2 at the border or in health care facilities and to prevent the spread of the virus into the community.

Further immunisation measures are likely to be implemented as other vaccines become available.

5.8.1. Post-exposure prophylaxis and outbreak control

Currently, there is no information on the use of mRNA-CV for post-exposure prophylaxis or outbreak control.

5.9. Variations from the vaccine data sheet

None applicable.

References

  1. V'Kovski P, Kratzel A, Steiner S, et al. Coronavirus biology and replication: implications for SARS-CoV-2. Nature Reviews: Microbiology, 2020: p. 1-16.
  2. Walls AC, Park YJ, Tortorici MA, et al. Structure, function, and antigenicity of the SARS-CoV-2 spike glycoprotein. Cell, 2020. 181(2): p. 281-292 e6.
  3. Lam TT, Jia N, Zhang YW, et al. Identifying SARS-CoV-2-related coronaviruses in Malayan pangolins. Nature, 2020. 583(7815): p. 282-285.
  4. Xiao K, Zhai J, Feng Y, et al. Isolation of SARS-CoV-2-related coronavirus from Malayan pangolins. Nature, 2020. 583(7815): p. 286-9.
  5. Geoghegan JL, Ren X, Storey M, et al. Genomic epidemiology reveals transmission patterns and dynamics of SARS-CoV-2 in Aotearoa New Zealand. Nat Commun, 2020. 11(1): p. 6351.
  6. Hussein M, Toraih E, Elshazli R, et al. Meta-analysis on serial intervals and reproductive rates for SARS-CoV-2. Annals of Surgery, 2021. 273(3): p. 416-423.
  7. Horby P, Huntley C, Davies N, et al. 2021 NERVTAG note of B.1.1.7 severity. Government U. URL: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/955239/NERVTAG_paper_on_variant_of_concern__VOC__B.1.1.7.pdf. (accessed 5 February 2021)
  8. Public Health England. 2020 Investigation of novel SARS-CoV-2 variant. Variant of Concern 202012/01. Technical briefing 2. England PH. URL: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/949639/Technical_Briefing_VOC202012-2_Briefing_2_FINAL.pdf. (accessed 5 February 2021)
  9. Cevik M, Tate M, Lloyd O, et al. SARS-CoV-2, SARS-CoV, and MERS-CoV viral load dynamics, duration of viral shedding, and infectiousness: a systematic review and meta-analysis. The Lancet Microbe, 2021. 2(1): p. e13-e22.
  10. Zou L, Ruan F, Huang M, et al. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. New England Journal of Medicine, 2020. 382(12): p. 1177-1179.
  11. Singanayagam A, Patel M, Charlett A, et al. Duration of infectiousness and correlation with RT-PCR cycle threshold values in cases of COVID-19, England, January to May 2020. Euro Surveillance, 2020. 25(32).
  12. Bai Y, Yao L, Wei T, et al. Presumed asymptomatic carrier transmission of COVID-19. JAMA, 2020. 323(14): p. 1406-07.
  13. Liu Y, Yan LM, Wan L, et al. Viral dynamics in mild and severe cases of COVID-19. Lancet Infectious Diseases, 2020. 20(6): p. 656-7.
  14. Piccoli L, Ferrari P, Piumatti G, et al. Risk assessment and seroprevalence of SARS-CoV-2 infetion in healthcare workers of COVID-19 and non-COVID-19 hospitals in Southern Switzerland. The Lancet Regional Health - Europe, 2021. 1.
  15. Hall VJ, Foulkes S, Charlett A, et al. SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN). The Lancet, 2021. 397(10283): p. 1459-1469.
  16. Lumley SF, O'Donnell D, Stoesser NE, et al. Antibody status and incidence of SARS-CoV-2 infection in health care workers. New England Journal of Medicine, 2021. 384(6): p. 533-540.
  17. Whitcombe AL, McGregor R, Craigie A, et al. Comprehensive analysis of SARS-CoV-2 antibody dynamics in New Zealand. medRxiv (preprint published online 11 December 2020), 2020.
  18. Viner RM, Mytton OT, Bonell C, et al. Susceptibility to SARS-CoV-2 infection among children and adolescents compared with adults: A systematic review and meta-analysis. JAMA Pediatr, 2021. 175(2): p. 143-156.
  19. Ward JL, Harwood R, Smith C, et al. 2021 (preprint). Risk factors for intensive care admission and death amongst children and young people admitted to hospital with COVID-19 and PIMS-TS in England during the first pandemic year. medRxiv. DOI: 10.1101/2021.07.01.21259785 (accessed
  20. Goldstein E, Lipsitch M ,Cevik M. On the effect of age on the transmission of SARS-CoV-2 in households, schools and the community. Journal of Infectious Diseases, 2021. 223(3): p. 362-9.
  21. Lopez Bernal J, Panagiotopoulos N, Byers C, et al. Transmission dynamics of COVID-19 in household and community settings in the United Kingdom. medRxiv (preprint published online 22 August), 2020 (preprint).
  22. Reddy RK, Charles WN, Sklavounos A, et al. The effect of smoking on COVID-19 severity: A systematic review and meta-analysis. Journal of Medical Virology, 2021. 93(2): p. 1045-1056.
  23. Williamson EJ, Walker AJ, Bhaskaran K, et al. Factors associated with COVID-19-related death using OpenSAFELY. Nature, 2020. 584(7821): p. 430-436.
  24. Shah ASV, Wood R, Gribben C, et al. Risk of hospital admission with coronavirus disease 2019 in healthcare workers and their households: nationwide linkage cohort study. BMJ, 2020. 371: p. m3582.
  25. Arons MM, Hatfield KM, Reddy SC, et al. Presymptomatic SARS-CoV-2 infections and transmission in a skilled nursing facility. New England Journal of Medicine, 2020. 382(22): p. 2081-2090.
  26. Jefferies S, French N, Gilkison C, et al. COVID-19 in New Zealand and the impact of the national response: a descriptive epidemiological study. Lancet Public Health, 2020. 5(11): p. e612-e623.
  27. Kotlar B, Gerson E, Petrillo S, et al. The impact of the COVID-19 pandemic on maternal and perinatal health: a scoping review. Reprod Health, 2021. 18(1): p. 10.
  28. Lokken E, Huebner E, Taylor GG, et al. Disease severity, pregnancy outcomes and maternal deaths among pregnant patients with SARS-CoV-2 infection in Washington State. American Journal of Obstetrics and Gynecology, 2021.
  29. Zambrano LD, Ellington S, Strid P, et al. Update: Characteristics of symptomatic women of reproductive age with ;aboratory-confirmed SARS-CoV-2 infection by pregnancy status - United States, January 22-October 3, 2020. MMWR: Morbidity and Mortality Weekly Report, 2020. 69(44): p. 1641-1647.
  30. Allotey J, Stallings E, Bonet M, et al. Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis. BMJ, 2020. 370: p. m3320.
  31. Adhikari EH, Moreno W, Zofkie AC, et al. Pregnancy outcomes among women with and without severe acute respiratory syndrome coronavirus-2 infection. JAMA Netw Open, 2020. 3(11): p. e2029256.
  32. Liguoro I, Pilotto C, Bonanni M, et al. SARS-COV-2 infection in children and newborns: a systematic review. European Journal of Pediatrics, 2020. 179(7): p. 1029-1046.
  33. Greenhalgh T, Knight M, A'Court C, et al. Management of post-acute covid-19 in primary care. BMJ, 2020. 370: p. m3026.
  34. Sivan M ,Taylor S. NICE guideline on long COVID. BMJ, 2020. 371: p. m4938.
  35. Sudre C, Murray B, Varsavsky T, et al. Attributes and predictors of Long-COVID: analysis of COVID cases and their symptoms collected by the Covid Symptoms Study App. medRxiv (preprint published online 19 December), 2020.
  36. Del Rio C, Collins LF ,Malani P. Long-term health consequences of COVID-19. JAMA, 2020.
  37. Carter MJ, Shankar-Hari M ,Tibby SM. Paediatric inflammatory multisystem syndrome temporally-associated with SARS-CoV-2 infection: an overview. Intensive Care Medicine, 2021. 47(1): p. 90-93.
  38. Jiang L, Tang K, Levin M, et al. COVID-19 and multisystem inflammatory syndrome in children and adolescents. Lancet Infectious Diseases, 2020. 20(11): p. e276-e288.
  39. Allen H, Vusirikala A, Flannagan J, et al. Increased household transmission of COVID-19 cases associated with SARS-CoV-2 Variant of Concern B.1.617.2: a national case-control study. 2021 (preprint).
  40. Centers for Disease Control and Prevention. 2021 SARS-CoV-2 Variant Classification and Definitions. US Department of Health and Human Services; 2021 [updated 25 May 2021]; URL: https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html. (accessed 31 May 2021)
  41. Our World in Data. 2021 Mortality risk of COVID-19.  2021; URL: https://ourworldindata.org/mortality-risk-covid. (accessed 02 February 2021)
  42. Roser M, Ritchie H, Ortiz-Ospina E, et al. 2020 Coronavirus pandemic (COVID-19). Published online at OurWorldInData.org; 2020; URL: https://ourworldindata.org/coronavirus'. (accessed 1 February 2021)
  43. Callaway E. The race for coronavirus vaccines: a graphical guide. Nature, 2020. 580(7805): p. 576-7.
  44. Flanagan KL, Best E, Crawford NW, et al. Progress and pitfalls in the quest for effective SARS-CoV-2 (COVID-19) vaccines. Frontiers in Immunology, 2020. 11: p. 579250.
  45. Walsh EE, Frenck RW, Jr., Falsey AR, et al. Safety and immunogenicity of two RNA-based Covid-19 vaccine candidates. New England Journal of Medicine, 2020. 383(25): p. 2439-2450.
  46. Mulligan MJ, Lyke KE, Kitchin N, et al. Phase I/II study of COVID-19 RNA vaccine BNT162b1 in adults. Nature, 2020. 586(7830): p. 589-593.
  47. Frenck RW, Klein NP, Kitchin N, et al. Safety, Immunogenicity, and Efficacy of the BNT162b2 Covid-19 Vaccine in Adolescents. New England Journal of Medicine, 2021.
  48. Polack FP, Thomas SJ, Kitchin N, et al. Safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine. New England Journal of Medicine, 2020. 383(27): p. 2603-2615.
  49. Dagan N, Barda N, Kepten E, et al. BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Mass Vaccination Setting. New England Journal of Medicine, 2021.
  50. Lopez Bernal J, Andrews N, Gower C, et al. Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant. New England Journal of Medicine, 2021.
  51. Thompson M, Burgess J, Naleway A, et al. Interim estimates of vaccine effectiveness of BNT162b2 and mRNA-1273 COVID-19 vaccines in preventing SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers — eight U.S. locations, December 2020–March 2021. MMWR: Morbidity and Mortality Weekly Report, 2021.
  52. Harris R, Hall J, Zaidi A, et al. Impact of vaccination on household transmission of SARS-CoV-2 in England. 2021 (preprint).
  53. Collier DA, De Marco A, Ferreira IATM, et al. Sensitivity of SARS-CoV-2 B.1.1.7 to mRNA vaccine-elicited antibodies. Nature, 2021. 593(7857): p. 136-141.
  54. Shimabukuro TT, Kim SY, Myers TR, et al. Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons. New England Journal of Medicine, 2021.
  55. Perl SH, Uzan-Yulzari A, Klainer H, et al. SARS-CoV-2-specific antibodies in breast milk after COVID-19 vaccination of breastfeeding women. JAMA, 2021. 325(19): p. 2013-2014.
  56. Prabhu M, Murphy EA, Sukhu AC, et al. Antibody response to Coronavirus Disease 2019 (COVID-19) messenger RNA vaccination in pregnant women and transplacental passage into cord blood. Obstetrics and Gynecology, 2021. Latest Articles: p. 10.1097/AOG.0000000000004438.
  57. Rottenstreich A, Zarbiv G, Oiknine-Djian E, et al. Efficient maternofetal transplacental transfer of anti-SARS-CoV-2 spike antibodies after antenatal SARS-CoV-2 BNT162b2 mRNA vaccination. medRxiv, 2021 (Preprint): p. 2021.03.11.21253352.
  58. Shimbabukuro T ,CDC-COVID-19 Vaccine Task Force. 2021 COVID-19 vaccine safety update. . (ACIP) ACoIP. URL: https://www.cdc.gov/vaccines/acip/meetings/slides-2021-1-27-21.html. (accessed 5 February 2021)
  59. Edmonds CE, Zuckerman SP ,Conant EF. Management of unilateral axillary lymphadenopathy detected on breast MRI in the era of coronavirus disease (COVID-19) vaccination. AJR: American Journal of Roentgenology, 2021.
  60. Pfizer New Zealand. 2021 New Zealand Datasheet: Comirnaty COVID-19 vaccine. Medsafe. URL: https://www.medsafe.govt.nz/profs/Datasheet/c/comirnatyinj.pdf. (accessed 5 February 2021)
  61. World Health Organization. 2021 COVID-19 subcommittee of the WHO Global Advisory Committee on Vaccine Safety (GACVS): updated guidance regarding myocarditis and pericarditis reported with COVID-19 mRNA vaccines.: WHO; 2021 [updated 9 July 2021]; URL: https://www.who.int/news/item/09-07-2021-gacvs-guidance-myocarditis-pericarditis-covid-19-mrna-vaccines. (accessed 12 July 2021)
  62. Diaz GA, Parsons GT, Gering SK, et al. 2021. Myocarditis and Pericarditis After Vaccination for COVID-19. JAMA. DOI: 10.1001/jama.2021.13443 (accessed 16 August 2021)
  63. World Health Organization. 2021 GACVS COVID-19 Vaccine Safety Subcommittee meeting to review reports of deaths of very frail elderly individuals vaccinated with Pfizer BioNTech COVID-19 vaccine, BNT162b2. World Health Organization (WHO); 2021 [updated 22 January 2021]; URL: https://www.who.int/news/item/22-01-2021-gacvs-review-deaths-pfizer-biontech-covid-19-vaccine-bnt162b2. (accessed
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