Mixed vaccine dose of AstraZeneca followed by Pfizer boosts neutralising antibodies, says South Korea study

A new study done in South Korea found that people who received mixed COVID-19 vaccination consisting of a dose of Oxford-AstraZeneca followed by a Pfizer-BioNTech vaccine shot shows more neutralizing antibodies than two AstraZeneca shots. AstraZeneca vaccine is manufactured and administered in India under the trade name Covishield.

The study comes as a form of validation for many countries which opted to offer the option of choosing alternatives as the second shot after taking the AstraZeneca vaccine as their first dose. The move by such countries came after reports emerged of rare blood clots as a rare side-effect of the AstraZeneca vaccine. 

As per the study which was conducted on 499 medical workers, the mixed vaccination regimen where a first of AstraZeneca dose was followed by a Pfizer dose boosts the neutralising antibody levels as much as six times in comparison to a regular two-dose AstraZeneca regimen.

100 participants out of the total 499 had taken a mixed AstraZeneca-Pfizer COVID-19 vaccine combo while 200 had two Pfizer doses and remaining 199 had a double dose of the AstraZeneca vaccine.

As per a Reuters report, the participants with mixed dose showed much greater antibodies than those that had taken two AstraZeneca shots.