New AstraZeneca COVID-19 vaccine data further support its use as third dose booster

New data from ongoing trial showed increased antibody response against Beta, Delta, Alpha, and Gamma variants following third dose booster with AstraZeneca COVID-19 vaccine. Additional analysis showed increased antibody response to Omicron after a third dose.

Positive results from a preliminary analysis of an ongoing safety and immunogenicity trial showed that AstraZeneca COVID-19 vaccine, when given as a third dose booster, increased the immune response to Beta, Delta, Alpha, and Gamma SARS-CoV-2 variants, while a separate analysis of samples from the trial showed increased antibody response to the Omicron variant.

The results were observed among individuals previously vaccinated with either AstraZeneca COVID-19 vaccine or an mRNA vaccine.

A separate Phase IV trial reported in a preprint with The Lancet on SSRN showed that a third dose of AstraZeneca COVID-19 vaccine substantially increased antibody levels following a primary vaccine series with CoronaVac (Sinovac Biotech).

These data add to the growing body of evidence supporting vaccine brand as a third dose booster irrespective of the primary vaccination schedules tested. The company is submitting these additional data to health authorities around the world given the urgent need for third dose boosters.

“AstraZeneca COVID-19 Vaccine has protected hundreds of millions of people from COVID- 19 around the world and these data show that it has an important role to play as a third dose booster, including when used after other vaccines. Given the ongoing urgency of the pandemic and AstraZeneca COVID-19 vaccine increased immune response to the Omicron variant, we will continue to progress regulatory submissions around the world for its use as a third dose booster,” says Mene Pangalos, executive vice president, BioPharmaceuticals R&D, AstraZeneca,

“These important studies show that a third dose of AstraZeneca COVID-19 vaccine after two initial doses of the same vaccine, or after mRNA or inactivated vaccines, strongly boosts immunity against COVID-19,” says Professor Sir Andrew J Pollard, chief investigator and director of the Oxford Vaccine Group at the University of Oxford. “The Oxford-AstraZeneca vaccine is suitable as an option to enhance immunity in the population for countries considering booster programs, adding to the protection already demonstrated with the first two doses.”

The safety and immunogenicity trial showed that AstraZeneca COVID-19 vaccine continued to be generally well tolerated. Further analyses from the trial are expected in the first half of 2022.

Previous studies support the COVID-19 vaccine brand as a third dose booster as part of a homologous or heterologous schedule. In a sub-analysis from two separate trials, a third dose of the vaccine given at least six months after a second dose significantly boosted antibody levels and maintained T cell response. It also resulted in higher neutralizing activity against the Alpha, Beta, and Delta variants, compared with a two-dose regimen.

The COV-BOOST trial also showed that a third dose booster of AstraZeneca COVID-19 induced significantly higher immune responses compared with controls against the Delta variant and original strain following a primary vaccine series of AstraZeneca COVID-19 or Pfizer BioNtech.