DOST-funded COVID-19 vaccine mix-and-match study underway

MANILA, Philippines — The government-funded study to mix and match COVID-19 vaccines is underway and expected to be completed by the end of the year, the Department of Science and Technology (DOST) said over the weekend.

Science Secretary Fortunato dela Peña said that the study had actually started last Nov. 17, conducted by a Philippine Society for Allergy, Asthma and Immunology project team led by Dr. Michelle de Vera.

As of Dec. 28, Dela Peña said that there have been 302 participants enrolled and vaccinated with a first dose, and 33 have already received a second dose.

The study targets to enrol 3,000 participants aged 18 and above in eight sites in Metro Manila, Cebu and Davao.

“The 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 in those given Sinovac as the first dose,” Dela Peña said.

He told The STAR that the clinical trial team will do an interim analysis once one-third of the participants or 1,000 people are vaccinated.

Earlier, the DOST said that China-made Sinovac was used as the first dose in the study since its supply in the country was most stable at that time.

Used as secondary doses in the study were Russia-made Sputnik V, United Kingdom-made AstraZeneca, and United States brands Pfizer-BioNTech and Moderna.

The DOST had provided a funding of P133 million for the study.

Under Group A of the study, scientists focus the same vaccines under the same platform. Group B will study the vaccines to be interchanged, and Group C will study 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 of the study.

For Group B, the vaccines to be combined after the first Sinovac dose are the other vaccines that have been granted emergency use authorization by the Food and Drug Administration.

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 the 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 administration of a booster dose from a different vaccine platform or brand.

The vaccine mix-and-match trials do not include people aged below 17.