What we know about how COVID-19 has spread since the virus arrived in New Zealand.
Last updated 1pm 20 April 2021.
All data on this page is as at 9:00 am on 20 April 2021 unless otherwise stated.
Data is collected from the EpiSurv database (administered by ESR) unless otherwise stated.
On this page:
When new cases are reported, isolated and investigated, we learn more about how COVID-19 has spread.
When clusters emerge, moving to Alert Levels 3 and 4 has slowed the spread of the disease.
Each person within a cluster with a confirmed or probable case of COVID-19 is asked:
- if they recently travelled overseas
- who they've spent time with
- where they've been (eg, shops, medical centres).
Health professionals and scientists can use this information to stop further transmission by:
- finding out how each person may have caught the disease
- monitoring how the disease is spreading.
If COVID-19 was spreading rapidly, investigating every case would be more difficult for our health system.
|Number of cases||Percentage (%) of all NZ cases|
|Imported case 1||1431||55%|
|Import-related case 2||491||19%|
|Locally acquired, linked 3||576||22%|
|Locally acquired, unknown source 4||96||4%|
- International passengers and crew entering the country who caught COVID-19 overseas or during the journey
- People exposed to international returnees - includes close contacts, other returnees in managed isolation or quarantine, and staff working at the border or in managed facilities
- Caught COVID-19 from someone locally
- Caught COVID-19 within NZ (hadn't travelled overseas recently or been in close contact with someone who travelled recently) but source is unknown
Daily confirmed and probable cases by source
|Māori||Pacific peoples||Asian||Middle Eastern/Latin American/African||European/Other||Unknown|
|Locally acquired case, unknown source||10||10||14||5||57||0|
|Locally acquired, epidemiologically linked||71||145||130||16||214||0|
Clusters of cases are groups of ten or more people who likely caught the disease from one another.
Clusters generally start where people are together in one place. Examples include:
- a holiday or a special event (on a cruise ship, at a conference, attending weddings)
- in their community
- at care homes for the elderly
- at a school.
Clusters are investigated and managed by public health officials. This includes confirmed and probable cases.
Public health staff quickly:
- follow up any cases of COVID-19
- find out who the person was with recently (close contacts)
- ask close contacts to isolate as well.
This action contains the clusters and prevents the disease spreading any further.
|Cluster under investigation||Location||Total to date||New cases in last 24 hours||Current active cases||Origin||Status*|
|Auckland February Cluster||Auckland||15||0||0||Under investigation||Closed|
|International Mariners||Christchurch||33||0||0||Overseas exposure||Closed|
|Auckland August Cluster||Auckland||179||0||0||Under investigation||Closed|
|Aged Residential Care Facility (2)||Auckland||13||0||0||Overseas exposure||Closed|
|Aged Residential Care Facility (1)||Auckland||51||0||0||Unknown||Closed|
|Aged Residential Care Facility (1)||Christchurch||56||0||0||Unknown||Closed|
|Aged Residential Care Facility (2)||Christchurch||19||0||0||Unknown||Closed|
|Group travel to USA||Auckland||16||0||0||Overseas exposure||Closed|
|Ruby Princess Cruise Ship Cluster||Hawke's Bay||25||0||0||Overseas exposure||Closed|
|Hospitality Venue||Matamata||77||0||0||Overseas exposure||Closed|
|World Hereford Conference||Queenstown||39||0||0||Overseas exposure||Closed|
|Aged Residential Care Facility||Waikato||15||0||0||Overseas exposure||Closed|
|Group Travel to USA||Wellington||16||0||0||Overseas exposure||Closed|
* A cluster of cases is considered closed if there are no new cases for 28 days after the people involved completed their time in isolation (28 days is twice the length of the incubation period of COVID-19).