ABSTRACT
BACKGROUND: There is very little known about SARS-CoV-2 vaccine immune responses in New Zealand populations at greatest risk for serious COVID-19 disease. METHODS: This prospective cohort study assessed immunogenicity in BNT162b2 mRNA vaccine recipients in New Zealand without previous COVID-19, with enrichment for Maori, Pacific peoples, older adults ≥ 65 years of age, and those with co-morbidities. Serum samples were analysed at baseline and 28 days after second dose for presence of quantitative anti-S IgG by chemiluminescent microparticle immunoassay and for neutralizing capacity against Wuhan, Beta, Delta, and Omicron BA.1 strains using a surrogate viral neutralisation assay. RESULTS: 285 adults with median age of 52 years were included. 55% were female, 30% were Maori, 28% were Pacific peoples, and 26% were ≥ 65 years of age. Obesity, cardiac and pulmonary disease and diabetes were more common than in the general population. All participants received 2 doses of BNT162b2 vaccine. At 28 days after second vaccination, 99.6% seroconverted to the vaccine, and anti-S IgG and neutralising antibody levels were high across gender and ethnic groups. IgG and neutralising responses declined with age. Lower responses were associated with age ≥ 75 and diabetes, but not BMI. The ability to neutralise the Omicron BA.1 variant in vitro was severely diminished but maintained against other variants of concern. CONCLUSIONS: Vaccine antibody responses to BNT162b2 were generally robust and consistent with international data in this COVID-19 naïve cohort with representation of key populations at risk for COVID-19 morbidity. Subsequent data on response to boosters, durability of responses and cellular immune responses should be assessed with attention to elderly adults and diabetics.
Subject(s)
COVID-19 Vaccines , COVID-19 , Aged , Antibodies, Neutralizing , Antibodies, Viral , BNT162 Vaccine , COVID-19/prevention & control , Female , Humans , Immunogenicity, Vaccine , Immunoglobulin G , Male , Middle Aged , New Zealand/epidemiology , Prospective Studies , SARS-CoV-2 , Vaccines, Synthetic , mRNA VaccinesABSTRACT
Development of safe and effective COVID-19 vaccines is a global priority and the best hope for ending the COVID-19 pandemic. Remarkably, in less than 1 year, vaccines have been developed and shown to be efficacious and are already being deployed worldwide. Yet, many challenges remain. Immune senescence and comorbidities in aging populations and immune dysregulation in populations living in low-resource settings may impede vaccine effectiveness. Distribution of vaccines among these populations where vaccine access is historically low remains challenging. In this Review, we address these challenges and provide strategies for ensuring that vaccines are developed and deployed for those most vulnerable.