COVID-19: Pfizer vaccine

The Pfizer vaccine has been approved for people 16 years and older. Find out more about the safety, effectiveness and side effects.

Last updated: 20 April 2021

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The Pfizer vaccine has been approved to use in New Zealand for people 16 years and older.

We've now secured 10 million doses of the Pfizer vaccine in total. This is enough for 5 million people to get the two doses of the vaccine they need against COVID-19.

How Pfizer works

Vaccines protect your health and prevent disease by working with your body’s natural defences, so you’re ready to fight the virus if you’re exposed.

The Pfizer vaccine will not give you COVID-19. It does not contain any live virus, or dead or deactivated virus. It works by triggering your immune system to produce antibodies and blood cells that work against the COVID-19 virus.

How the vaccine is given

Pfizer is given as an injection into the muscle of your upper arm.

You’ll need two doses. The second dose is given at least three weeks later. It’s very important you get your second dose, you have your best protection once you have both doses.

Staff will observe you for at least 20 minutes after your injection.

Effectiveness and protection

Getting a COVID-19 vaccine is an important step you can take to protect yourself from the effects of the virus.  

As with any vaccine, Pfizer may not fully protect everyone who gets it. The clinical trials performed on the Pfizer vaccine show it's approximately 95% effective against symptomatic COVID-19, seven days after receiving two doses.

We don’t yet know how long you’ll be protected or if it will stop you from catching and passing on the virus. Research has shown that immunity following natural infection remains for at least eight months and we have every expectation the vaccine immunity will be even longer.

Side effects and reactions to Pfizer

Like all medicines, the vaccine may cause side effects in some people. These are common, are usually mild and don’t last long. They may be more common after your second dose.

See the list of known side effects

What’s in the Pfizer vaccine

Pfizer is a mRNA-based (messenger ribonucleic acid) vaccine.

The Pfizer vaccine does not contain any live, dead or deactivated viruses. There are no animal products in this vaccine.

Active ingredient

30µg of a nucleoside modified messenger RNA encoding the viral spike (S) glycoprotein of SARS-CoV-2


These ingredients make up the lipid nanoparticle which is the transport mechanism for the active ingredient to make it inside a cell without being broken down.

  • 0.43 mg (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)
  • 0.05 mg 2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
  • 0.09 mg 1,2-distearoyl-sn-glycero-3- phosphocholine
  • 0.2 mg cholesterol


These ingredients help make sure the vaccine pH is close to that of human cells.

  • 0.01 mg potassium chloride
  • 0.01 mg monobasic potassium phosphate
  • 0.36 mg sodium chloride
  • 0.07 mg dibasic sodium phosphate dihydrate


This ingredient protects the lipid nanoparticle at very cold temperatures (-80 degrees celcius that the vaccine is stored at).

6 mg sucrose

Monitoring international use of Pfizer

We’re aware of several deaths in elderly people in Norway who had received the Pfizer vaccine. Reports say the deaths were very frail patients who may have had only weeks or months to live. There is no confirmation they were linked to the vaccine. These deaths are being investigated further.

Medsafe is closely monitoring this as well as the results of the vaccine roll-out out in other countries. This will add to the clinical data we expect to receive from Pfizer. Including:

  • the overall safety profile of the vaccine
  • any reported reactions (the frequency, the severity, and any previously unknown reactions).

Vaccine data

Our vaccination dashboard shows a snapshot of our vaccination progress. You can see the number of people who have received the Pfizer vaccination in New Zealand so far.

Vaccine data

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