UK study finds mRNA vaccines provide biggest booster impact

Covid-19 vaccines made by Pfizer and Moderna that use mRNA technology provide the biggest boost to antibody levels when given 10-12 weeks after the second dose, a British study published on Thursday has found.

When AstraZeneca, Novavax, Johnson & Johnson and Curevac were given as boosters, they increased antibody levels for either initial vaccine, albeit to a smaller degree. However, while Valneva boosted antibodies in people initially vaccinated with AstraZeneca, it did not provide a boost for Pfizer. The study found that booster shots also helped to generate a broad T-cell response against the Beta and Delta variants, which may play a key role in longer-term protection. [Reuters]