COVID-19 vaccine booster increases antibody responses: NIH study

A booster dose of the Moderna (mRNA-1273) COVID-19 vaccine given to rhesus macaques about six months after their primary vaccine series significantly increased levels of neutralising antibodies against all known SARS-CoV-2 variants of concern, according to a new study from US-based National Institutes of Health (NIH) scientists and colleagues. The study, published in Science, also showed that the increased neutralising antibody responses were sustained for at least eight weeks after the boost, were significantly higher than after the primary vaccine series, and generated high-level protection, meaning the ability to significantly limit virus from replicating in the lungs and nose. These data suggest that boosting triggers a strong immune memory response and potentially longer lasting immunity. The researchers also determined that both the mRNA-1273 vaccine developed to target the original SARS-CoV-2 virus and a slightly modified version of the vaccine targeting the Beta variant, were equivalent in their ability to boost antibody responses and protect.