A long term surveillance study could hold the clues to developing a Covid-19 vaccine.
The national lab, ESR monitors more than 2000 people as part of large scale research into influenza and its vaccine effectiveness.
The programmes, called SHIVERS II and WellKiwis look at both adults over a number of years and new-borns to age seven.
The study's principal investigator, Dr Sue Huang, said expanding to include the Covid-19 virus will help global research to better understand the pandemic.
Participants have swabs and blood taken every season to monitor for influenza, but a test for SARS-CoV-2 - the virus that causes Covid-19 - will also be added.
Dr Huang said this would help to get a clearer picture of the virus and what it looks like in a New Zealand population.
"This is a very new virus, we have a lot of knowledge gaps.
"We want to understand all those details and through this study we hope that understanding will help guide vaccine development, or guide immune therapy approach."
There was still little information about how people infected with the virus developed antibodies, she said.
Or why young children got milder illnesses, while elderly people were more prone to severe disease.
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It was important to understand the difference in immune systems and why people presented differently, she said.
As well as helping research into a vaccine, the long term study from various tests would give researchers more data.
"That gives us an understanding about the population immunity against the Covid virus, and at the same time if people haven't been infected with the Covid virus then we would know they don't have immunity and they would be susceptible to the Covid virus."
Public Health officials would ultimately be able to use the data to tailor their response, Dr Huang said.
"Knowing the proportion of asymptomatic or mildly ill cases is important as it will help us to understand what is driving this Covid-19 pandemic."
The studies have previously been limited to one participant in the home, but now involve the whole household because of the information that can be gathered about how the virus spreads.
"The household is a valuable setting to understand the chain of transmission, the clinical spectrum of illness and the amount and duration of virus being shed from infected individuals."