Data from a new laboratory study at the University of Oxford has revealed that AstraZeneca’s COVID-19 vaccine significantly boosted levels of antibodies against the Omicron SARS-CoV-2 variant. This is following a third dose booster. Neutralisation titres for Omicron were boosted following a third dose with COVID-19 Vaccine AstraZeneca compared to titres after a second dose.

Likewise, levels seen after the third dose booster were higher than the neutralising antibodies found in individuals who had been previously infected with and recovered naturally from COVID-19. This applies to the Alpha, Beta, Delta and the original strain. Sera obtained from individuals one month after receiving the third dose booster vaccination neutralised the Omicron variant to levels that were broadly similar to those observed one month after the second dose against the Delta variant.

The study analyzed blood samples taken from individuals infected with COVID-19, those who had been vaccinated with a two-dose schedule and a third dose booster. It also included those who had reported previous infection from other COVID-19 variants of concern. The study included samples from 41 individuals who had received three doses of COVID-19 Vaccine AstraZeneca.

Commenting on the new findings, Professor Sir John Bell, Regius Professor of Medicine, University of Oxford said, “It is very encouraging to see that current vaccines have the potential to protect against Omicron following a third dose booster. These results support the use of third dose boosters as part of national vaccine strategies, especially to limit the spread of variants of concern, including Omicron.”

Data from another laboratory study support COVID-19 Vaccine AstraZeneca’s effect against Omicron, with individuals vaccinated with two doses of COVID-19 Vaccine AstraZeneca retaining neutralising activity against Omicron. However, a decrease was seen compared to the original strain. In other studies, COVID-19 Vaccine AstraZeneca has been shown to generate a diverse and durable T-cell response to multiple variants.

Currently, available data against variants of concern, excluding Omicron, support the use of a third booster with AstraZeneca COVID-19 vaccine as part of a homologous or heterologous schedule. A sub analysis from the COV001 and COV002 trials demonstrated that a third dose of COVID-19 Vaccine AstraZeneca given at least six months after a second dose boosted antibody levels six-fold and maintained T cell response. A third dose also resulted in higher neutralising activity against the Alpha, Beta, and Delta variants, compared with a two-dose regimen.