The Department of Science and Technology (DOST) and the Department of Health (DOH) will support a research which will look into the possibility of mixing and matching different COVID-19 vaccine brands and platforms through a study involving 3,000 Filipino participants starting June 2021.

“Ideally, an individual should complete two doses of vaccine using the same vaccine product. However, we cannot ignore the existing shortage in the global vaccine supply, which may interfere with the vaccine distribution and administration in the Philippines. It is urgently needed to ascertain the interchangeability of COVID-19 vaccines, as administering the second dose of vaccines with a two-dose regimen is vital in inducing the needed level of protection against the virus,” said DOST Secretary Fortunato de la Peña.

Aiming to determine the safety and analyze the immune response of individuals whose first dose is followed by a second dose of a different vaccine platform, the mixed-dose study will offer clinical data that will provide basis for the DOH in developing guidelines on the vaccination rollout, and on which vaccine regimen may be applied for an Emergency Use Authorization (EUA) during situations of limited vaccine supply.

Pending approval from the Food and Drug Administration (FDA) and health research ethics board, the study expects to enroll participants aged 18 years or older situated in eight priority areas for vaccine rollout following DOH allocation and the COVAX facility guidelines.

Secretary de la Peña further emphasized that the mixed-dose approach, if proven safe and effective, will help address possible shortage of vaccine products as interchangeable use of vaccine brands or platforms will offer flexibility in the vaccination rollout.

While there are similar studies being conducted in other countries, this study will specifically make use of vaccines being used in the country’s COVID-19 vaccination program and generate data from the Filipino people mixing COVID-19 vaccines after the first Sinovac vaccine dose which uses the inactivated virus platform. To be implemented by the Philippine Society for Allergy, Asthma and Immunology (PSAAI), with Dr. Michelle De Vera as the lead, the study will run for 18 months in conjunction with the vaccination rollout using the available vaccine supply in the Philippines.