Mixing AstraZeneca and Pfizer vaccines gives stronger immunity against COVID
People who have been double-dosed with the Oxford/AstraZeneca vaccine could have a stronger immune response if they were given a different jab as a booster, Sky News has reported based on new study findings.
Professor Matthew Snape from the Oxford Vaccine Group said the “mix and match” approach may result in additional protection against coronavirus.
The study, called Com-COV, compared mixed two-dose schedules of Pfizer and AstraZeneca vaccines, and found that in any combination, they produced high concentrations of antibodies against the coronavirus spike protein.
Results showed people who received the AstraZeneca vaccine first, followed four weeks later by a Pfizer dose, produced antibody levels nine times higher than those given two doses of the Oxford jab.
Matthew Snape, the Oxford professor behind the trial, said that the findings could be used to give flexibility to vaccine rollouts, but was not large enough to recommend a broader shift away from clinically approved schedules on its own.
“It’s certainly encouraging that these antibody and T-cell responses look good with the mixed schedules,” he told reporters.
“But I think your default has to stay, unless there’s a very good reason otherwise, to what is proven to work,” he added referring to the same-shot vaccine schedules assessed in clinical trials.
With the continuing global vaccine supply shortages and an increasing variety of COVID-19 vaccines approved for emergency use, many have wondered whether combining different vaccines could be a feasible option to fast-track and simplify vaccination efforts.
The short answer from the World Health Organization, following preliminary studies in Spain, the UK and Germany and evidence coming from real-life scenarios in India, is yes.
But so far it is only with an AstraZeneca first dose followed by a Pfizer vaccine as a second dose that we know for sure that this can be done “without any problems in the sense of efficacy,” said Alejandro Cravioto, WHO Chair of Strategic Management, when asked about the issue at an online question and answer session.
“We have over 15 vaccines now that are being used in different countries,” said Katherine O’Brien, WHO Director of Immunization, Vaccines and Biologicals department.