Department of Health (DOH) Undersecretary and treatment czar Leopoldo Vega said on Thursday, July 1, that mixing and matching different coronavirus disease (COVID-19) vaccines pose an advantage to countries where vaccine supplies are limited.

In a virtual Palace briefing, Vega said mixing doses of the Pfizer and AstraZeneca vaccines generate a stronger immune response.

"Very effective in terms of the result but this is just a very preliminary study. We still have to make use of the bigger clinical trial which is actually the same vaccine. But this study is a good chance and good also to recommend," he added.

"Probably in the near future, I think this will be a good advantage in countries where vaccines are limited. Mixing and matching would be a very good strategy to get the population vaccinated."

According to a study conducted by the University of Oxford, mixing AstraZeneca doses with Pfizer "generates an immune response that was above the threshold set by AstraZeneca vaccine."

An AstraZeneca shot followed by Pfizer produced the best T-cell responses and higher antibody response, the study published on the Lancet read.

T-cells are a group of immune cells that can target and destroy virus-infected cells.

Vega said the Philippines is still dependent on clinical trials done by the World Health Organization, but once a clear recommendation has been released by the agency, he believes that it would also be adopted by the national vaccination implementation.

On June 3, the Department of Science and Technology's study on the safety and efficacy of mixing and matching five COVID-19 jabs is expected to begin in July.

The trial will involve 3,000 participants who are aged 18 and above and come from A1 to A4 priority groups.

Related story: Mix and match: What you need to know about PH’s study on COVID-19 vaccine mixing, matching