A clinical study investigating immune responses to the Pfizer vaccine in New Zealanders at risk for COVID-19 disease has provided reassuring results says Dr Fran Priddy, the Executive Director of Vaccine Alliance Aotearoa New Zealand – Ohu Kaupare Huaketo (VAANZ).

The study, Ka Mātau, Ka Ora (from knowledge comes wellbeing) – the largest evaluation of COVID-19 vaccine immune responses in Māori and Pasifika – showed near universal strong immune responses in New Zealand vaccine recipients, after two doses.

“The results are reassuring given the study represented some of those New Zealanders most at risk for COVID disease – older adults, Māori, Pacific peoples, and those with co-morbidities like diabetes, obesity or heart disease,” says Dr Priddy. She notes it did not evaluate immunocompromised people.

“These results can give confidence to everyone who has received the Pfizer vaccine and those still undecided about getting vaccinated or boosted that this is an effective vaccine.”

The study assessed immune responses to the Pfizer-BioNTech vaccine in people with no prior exposure to COVID-19 28 days after second vaccination, evaluating the ability of vaccine-induced immune responses to neutralise viral variants.

“Antibody responses overall were robust and consistent with international data, and reassuringly were not related to ethnicity, gender or to overweight/obesity,” says Dr Priddy.

Similar to international data, neutralising responses to the Omicron variant were very low compared to the original strain, on which the Pfizer vaccine is based, and the Delta variant. This reinforces the need for people to get boosted says Dr Priddy.

Dr Priddy says reduced antibodies were also associated with age, with older groups having lower but adequate responses. “People 75 years and over had the lowest responses, but this was not unexpected. We know from international data they are at risk for decreasing antibody levels over time, which is why a booster dose is recommended.”

People with type 2 diabetes also had lower but sufficient antibody levels, independent of ethnicity or body mass index. “As the pandemic continues to evolve, older adults and people with diabetes should be included when considering policy decisions about additional booster doses,” says Dr Priddy.

The ongoing study is assessing response to boosters, durability of responses and T-cell immune responses.

Malaghan Institute Clinical Immunologist Dr Maia Brewerton says ongoing research will be important to monitor the difference seen in the immune response in our population following a booster dose, as more New Zealanders develop infection-induced or ‘hybrid’ immunity and as new variants arise.

“Not all antibodies are created equal and neutralising antibodies are particularly important because they can block the entry of the virus into host cells and prevent infection.”

She says while the study showed no difference in the antibody immune response in Māori when compared to non-Māori, the rates of infection and hospitalisation from COVID-19 remain higher amongst Māori and Pasifika.

“The importance of driving up vaccination rates and correcting health and social inequities to reduce the burden of disease amongst these groups remains critical.”

ENDS

Immunogenicity of BNT162b2 COVID-19 vaccine in New Zealand adults

Frances H Priddy, Michael Williams, Simon Carson, Brittany Lavender, Julia Mathieson, Chris Frampton, Nicole Jane Moreland, Reuben McGregor, Georgia Williams, Maia Brewerton, Katie Gell, James Ussher, Graham Le Gros

medRxiv 2022.04.05.22273480; doi: https://doi.org/10.1101/2022.04.05.22273480

BACKGROUND

Ka Mātau, Ka Ora

Ka Mātau, Ka Ora (from knowledge comes wellbeing) is a clinical study, funded by the Ministry of Health and the Ministry of Business, Innovation and Employment, to evaluate the immunogenicity of COVID-19 vaccine regimens in adults in New Zealand. It is being sponsored by the Malaghan Institute of Medical Research (as part of VAANZ) in collaboration with Pacific Clinical Research Network, the Ministry of Health and the Human Vaccines Project.

The study recruited 298 New Zealanders at Lakeland Clinical Trials in Rotorua and Southern Clinical Trials in Christchurch with a focus on Māori, Pasifika, older adults and those with co-morbidities associated with increased risk of COVID-19. The study will assess immune responses for up to 12 months after their last vaccine dose.

Vaccine Alliance Aotearoa New Zealand – Ohu Kaupare Huaketo (VAANZ)

VAANZ was established in 2020 as part of the Government’s COVID-19 vaccine strategy. Focused on building New Zealand’s capability and platforms for vaccine development to meet the current and future demands of infectious disease threats, VAANZ comprises the Malaghan Institute of Medical Research, the University of Otago, Victoria University of Wellington, ESR, South Pacific Sera, Avalia Immunotherapies and AgResearch, as well as a number of local and international collaborators.

With ongoing investment from the Government into 2022, VAANZ is now a public-private partnership, with additional private funding helping support vaccine development and establishment of an mRNA platform for New Zealand. VAANZ has pivoted to address two key concerns in the evolving pandemic – a booster vaccine for variants of concern, (Delta, Omicron) and vaccines to protect broadly across current and future SARS-CoV-2 variants and related coronaviruses. www.malaghan.org.nz/our-research/covid-19/