Study: mix and matching may increase antibodies


A new Spanish study suggests mix and matching different vaccine doses may increase antibodies.

More information is emerging on the topic of mix and matching COVID-19 vaccines. Preliminary findings from a Spanish study suggest that taking two distinct doses may actually increase antibodies. The study revealed their results at a press conference on Tuesday. The findings, moreover, appear to be the first indication of how successful combining vaccine doses might be. As part of the study, about 440 persons under the age of 60 who had already had AstraZeneca as their first dose received injections of the Pfizer-BioNtech vaccine.

The initial findings are consistent with those from the UK, which concluded that the combination was eventually safe. Sore arms, headaches, fever, and exhaustion were the most common adverse effects, however, they usually went away within two to three days. The study focused on understanding whether mixing two vaccine doses is ultimately successful. The success of the study paves the way for a deeper understanding of antibody response against coronavirus. Nonetheless, it’s crucial to highlight that the data must be vetted and published before it can be used.

The importance of mixing AstraZeneca and other vaccines

Some experts believe this is already a positive indicator. For example, Tania Watts, professor of immunology at the University of Toronto, while remarking that they still don’t have the actual data, it fits that findings show a boost of the immune response. “What we do know is it’s reassuring that people can have a different vaccine after AstraZeneca. And that this is both safe and looks like it’s quite effective to have that second boost. Especially with the second vaccine being an mRNA vaccine.”

Mixing and matching vaccinations have been a controversial topic from the start. This is especially important for those who had AstraZeneca as their first dose and then had to watch as the concerns over the vaccine rose. Even though over 2.1 million Canadians received AstraZeneca as their first dose, several municipalities paused its administration after three fatal cases of blood clots. Still, Canada holds on to over 250,000 doses, expiring in around a month. Therefore, mix and matching could be a fruitful solution to the urgency of distributing such doses without losing them.