The SARS-CoV-2 neutralising antibody profile of New Zealand adults in 2023: Impact of vaccination and infection

The successive dominance of SARS-CoV-2 omicron sublineages presents challenges for vaccination strategies with respect to the antigenic content of boosters. New Zealand's COVID-19 elimination strategy (2020−2021) ensured the major vaccination campaign (Pfizer-BioNTech BNT162b2) was completed pre-omicron in an infection-naive population, providing a unique setting to explore the impact of omicron infection waves on vaccine responses. This study compared neutralising antibodies (NAb) to eight SARS-CoV-2 omicron sublineages 28-days and 11-months after a third dose. Participants (n = 219) were classified by antigen exposure in the intervening 10 months including additional vaccinations and/or infections. Both vaccination and infection boosted NAb levels to all sublineages. Antigenic maps showed infection had a major impact on NAb breadth, despite all participants being vaccinated with an ancestral-based vaccine. While vaccination remains an important tool to boost immunity, the breadth of NAbs observed suggest that attempts to match booster specificity with current circulating variants may not always be necessary.