Philippine’s vaccine mix-and-match study awaits FDA nod

MANILA, Philippines — Filipino scientists are raring to begin a state-funded initiative to study the “mix-and-match” of a variety of vaccines being administered in the country’s mass immunization against COVID-19.

Department of Science and Technology (DOST) Secretary Fortunato dela Peña said the Philippine Society for Allergy, Asthma and Immunology (PSAAI) research team led by Dr. Michelle de Vera is all set to conduct the study once it secures approval from the Food and Drug Administration (FDA).

“This study is a multi-site, convenience sampling, unblinded trial which will determine the safety and immunogenicity of completing the vaccination series with available COVID-19 vaccines in the Philippines to those given Sinovac as the first dose,” said Dela Peña in his weekly virtual “Bayanihan” briefing.

The DOST has provided funding of P133 million for the study, but has been waiting for FDA approval since June so that De Vera’s team could start its work.

“The study is expected to enroll 3,000 participants aged 18 years old and above in eight sites in NCR (National Capital Region or Metro Manila), Cebu and Davao,” Dela Peña said.

Earlier, DOST said the study presupposes China-made Sinovac as the first dose since it is the vaccine which the country has the most stable supply in storage.

Secondary doses in the study are the Russian Sputnik V, the United Kingdom-developed AstraZeneca and the United States-made Pfizer-BIONTech and Moderna.

The DOST had also allocated P114.9 million for another study on the efficacy of the national COVID-19 vaccination program, which is being undertaken by the University of the Philippines-Manila (UP-Manila).

The study will have a Group A that studies the same vaccines under the same platform; a Group B that studies the vaccines to be interchanged and a Group C that studies the special high-risk group to be given a booster dose.

Under Group A, the completion of the Sinovac-Sinovac and AstraZeneca-AstraZeneca vaccination series will be studied to act as the control group of the study.

For Group B, the vaccines to be combined after the first Sinovac dose are the other vaccines that have already been given an emergency use authorization (EUA) by the FDA.

Group C will match the same set of vaccines but as a third dose.

Aside from determining the safety and immunogenicity of interchanging vaccine brands to complete COVID-19 vaccine series, the study also aims to determine if the high-risk population who already completed the dosing regimen of the Sinovac vaccine would elicit a better immune response after the immunization of a booster dose from a different vaccine platform or brand.

The trial will also analyze whether those who completed the dosing regimen for Sinovac will have a better immune response after receiving a booster dose of a different vaccine platform or brand.

The vaccine mix-and-match trial will not include people under 17 years old.