Hundreds of pregnant women in Wellington will be invited to have their baby join a world-first, international research project on flu.
Every year, up to 95 New Zealanders need intensive care treatment in hospital because of flu and up to 70 people die as a result of flu.
The annual jab offers protection, but researchers want to design a more effective vaccine that would last several years.
The $54 million project, funded by the National Institutes of Health in the US, is being carried out in three cities: Wellington, Los Angeles and Managua in Nicaragua.
In Wellington, researchers aim to enrol 200 women and babies each year for three years and monitor the 600 children for seven years.
The principal investigator of the WellKiwis study, Sue Huang from the Institute of Environmental Science and Research (ESR), said the way the body responds to a flu infection may be imprinted early in life.
"It's a bit like once you have a flu exposure for the first time you have some ... very, very strong childhood memory. When you encounter the virus for the second time it will recall this memory and mount a very, very good immune response," Dr Huang said.
This is known as the "birth effect" which Dr Huang said was seen following the 1918 Spanish flu pandemic. People born before 1957 who became exposed to this flu virus gained a strong immunity to the 2009 swine flu pandemic.
For the WellKiwis study, from today lead maternity carers and others will ask pregnant women for consent to take a sample of cord blood, from near the placenta, at their babies' birth.
ESR project midwife Karen Daniells said the painless test would provide a baseline blood sample.
When the baby is about two months old, mothers will be asked if they are happy for their child to be followed in the study for the next seven years.
Children will be monitored for flu-like illnesses. The study team will collect nasal swabs and blood samples to understand children's immune responses to flu viruses and flu vaccines.
Wellington Hospital paediatrician and infectious diseases expert Hazel Dobinson said it would be vital research in a key group.
"The target is to make sure we can address what happens to these children and infants to their immune system when they're exposed to the flu, get an understanding of that. And then that might make us be able to make a more effective vaccine in the future," Dr Dobinson said.
The study could shed light on other issues too.
"We can see if babies whose mothers were vaccinated in pregnancy are protected for longer, and how their immune system deals with their exposure to their first flu infection," she said.
The $5 million cost of the WellKiwis part of the international research will be funded by the US National Institutes of Health.