‘Mix-and-match’ COVID jabs?

Research has found that taking a “mix-and-match” approach is boosting protection against the virus and may be a solution for countries struggling with supply demands. So is it time Australia starts mixing it up? 

The right mix matters

Researchers at the UK’s University of Oxford this week released the latest findings from its “mixed” vaccine study. The Com-COV trial, which involved 830 volunteers aged over 50, revealed that combining Pfizer and AstraZeneca jabs not only provides a “robust” immune response, it also produces more antibodies than two AstraZeneca shots.

Both mixed schedules induced higher antibodies than two doses of AstraZeneca vaccine, but the double Pfizer jab still had the highest antibody response. Oksana Pyzik, an infectious diseases expert at University College London, said given there’s such an erratic supply of vaccines globally, this kind of mix-and-match trial was “really important”.

/  Oksana Pyzik, an infectious diseases expert at University College London

Why would Australia advise against mixing?

Health authorities say they have no plan to approve mixing COVID vaccines in Australia, with the vice-president of the Australian Medical Association even warning against it. 

Professor George Liu, a public health expert at La Trobe University, said at this stage research had only shown possible effects on immunity and not whether mixing two vaccines reduces the rare blood clots associated with the AstraZeneca vaccine.

“If you haven’t had any serious reaction to the first dose of AstraZeneca then there’s enough evidence to show the efficacy of the vaccine to continue with it.” However, if someone did have a serious adverse reaction to AstraZeneca, “then it would be reasonable to give those people a different second vaccine to ensure their safety,” he added.

Even if Australia was to approve the mixed vaccine approach, some experts say there wouldn’t be enough Pfizer to offer it to people for their second dose.

/  Professor George Liu