The Philippines has allocated P133 million to conduct a study on the safety of using different coronavirus disease (COVID-19) vaccine doses and vaccine platforms in Filipino adults, the Department of Science and Technology (DOST) said Friday, May 21.

DOST Secretary Fortunato “Boy” T. de la Peña said the study will be conducted by the Philippine Society for Allergy, Asthma, and Immunology (PSAAI), led by Dr. Michelle De Vera.

"This is a study which we refer to as mix and match. having two vaccines , one vaccine for the first does, another vaccine for the second dose,” he said during his weekly report on Friday.

The study is expected to "evaluate the safety and immunogenicity of mixing different COVID-19 vaccines and vaccine platforms in Filipino adults." It will be conducted for a period of 18 months starting from June 2021 up to November 2022 with financial backing from the DOST and Department of Health (DOH) amounting to P133 million.

"The study was brought about with the aim to contribute to addressing the COVID-19 vaccination concerns in the Philippines associated with the unpredictable vaccine supply,” de la Peña said.

He noted that the pressing need of the timely COVID-19 vaccination of the second dose conferring an individual to a more complete and protective immunity against SARS-CoV-2 prodded the conduct of the local study.

"Since Sinovac has been, shall we say, most stable vaccine supply in the country, the combinations will be between Sinovac and the other vaccines,” the DOST chief said.

The study also seeks to determine if the high-risk population who completed the dosing regimen of a vaccine would elicit a better immune response after the immunization of a booster dose.

"In this particular case, the adverse events will be monitored and evaluated as part of the study’s safety assessment,” de la Pena said.

While antibody tests will be done in five different time points to assess the immunogenicity of the different vaccine combinations, he said.

There are eight proposed study sites nationwide.

"Local clinical data to be generated from the Filipino people on the interchanging of available COVID-19 vaccines in the Philippines can serve as the basis for declining which vaccines/vaccine platforms can be mixed, which may be applied by the Department of Health (DOH) for an Emergency Use Authorization (EUA),” de la Peña said.

"The relevant data generated may provide basis for the guidelines/policies of the DOH on the vaccination rollout especially during situations of limited vaccine supplies or vaccine shortage,” he added.