Boosters 'significantly improve' body's Omicron response - study

A new study has demonstrated the importance of a booster vaccination in the body's fight against the Covid-19 Omicron variant.

The Ka Mātau, Ka Ora study is the largest evaluation yet of how Kiwis' immune systems have responded to the Covid-19 vaccine. It focused on populations at a higher risk from the virus, including Māori, Pasifika and the elderly.

It found that "a first booster dose significantly improves the ability of vaccine-induced immune responses to neutralise viral variants, including Omicron, across all demographic groups".

Dr Maia Brewerton, Vaccine Alliance Aotearoa New Zealand clinical director, said the results were a "clear call to action".

"Vaccination continues to be one of the best tools we have for protecting ourselves and our whānau from getting really sick from Covid-19. But two doses isn't enough," she said.

As well as Māori and Pasifika, Brewerton stressed the difference a booster dose can make for people with Type 2 diabetes.

Participants with diabetes saw a four-fold increase in antibody levels after a booster dose, compared to a two-fold increase in participants without diabetes.

It follows initial results published in April showed "an absence of neutralising capacity against Omicron" after two vaccine doses, despite "near-universal strong immune responses to the vaccine in participants".

"Our data shows that a booster was and remains crucial without natural infection and hybrid immunity, to produce a neutralising response against Omicron regardless of age, BMI, ethnicity, or presence or absence of diabetes," Brewerton said.

"This is particularly important for those vulnerable New Zealanders who have managed to avoid Covid-19 so far."

The call for eligible Kiwis to go out and get their booster comes as about 600,000 doses of the Pfizer Covid-19 vaccine are set to expire at the end of January.

At the moment, about 64,000 vaccinations are used each month.

Covid-19 cases are on the rise, with the Ministry of Health suggesting daily reported cases could reach 13,000 by the end of the month.