45 participants already enrolled in PH COVID-19 vaccine ‘mix and match’ trial

Published December 2, 2021, 1:40 PM

by Charissa Luci-Atienza 

The Department of Science and Technology (DOST) has logged more than 40 participants in the country’s “Mix and Match” (MnM) study.


The 18 month-long study seeks to evaluate the safety and immunogenicity of mixing different coronavirus disease (COVID-19) vaccines and vaccine platforms in Filipino adults. The project team is led by Dr. Michelle De Vera of the Philippine Society for Allergy, Asthma, and Immunology (PISAAI).

DOST Undersecretary for Research and Development Dr. Rowena Cristina L. Guevara said two of the five sites —Marikina City and Muntinlupa Cty were actively recruiting participants for the trial. The MnM study is expected to enroll 3,000 adult volunteers aged 18 and above.

“As of December 1, there had been a total of 45 vaccinated participants for the study with two out of five sites actively recruiting, namely: Marikina City and Muntinlupa City,” she told the Manila Bulletin in an interview.

She said Manila City was due to start recruitment and screening on Dec. 1.

“As for Davao City and Dasmariñas City, Cavite, the project team is closely coordinating with the local government units (LGUs) for the site preparations and other required documents to implement the study such as the endorsement letters from DOH and the City Mayors,” Guevara said.

She said both sites have been approved by their respective Institutional Review Boards (IRBs), as well as the Single Joint Research Ethics Board (SJREB).

“There is ongoing training of the other personnel for the operations of the study, specifically with regard to data collection, monitoring, and management,” she added.

Guevara noted that the Food and Drug Administration (FDA) has approved the application of PSAAI for their License-To-Operate (LTO) as sponsor on Nov. 29.

“There are no more pending applications with the Philippine FDA for the study.”

The MnM study has been given a total budget of P204.19 million under the DOST-Grants-in-Aid (GIA) program. It secured FDA’s approval on Nov. 16.

Guevara said as per the protocol, there will be two interim analyses planned for the study to evaluate the immune responses of the participants to the vaccine combinations and what would be the side effects, if any.

“The first interim analysis will be performed once 1,000 participants or one-third of the total 3,000 sample size have been enrolled and evaluated,” she said.

“The second interim analysis will be done when two-thirds of the total sample or 2,000 participants have been enrolled and evaluated.”

The study aims to 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.

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

Locally available vaccines under the National Immunization Program are expected to be used in the trial. These include Sinovac, Sputnik V, AstraZeneca, Pfizer and Moderna.

“These vaccines will be mixed-and-matched to determine the safety and immunogenicity of mixing different COVID-19 vaccine brands/platforms. The main vaccine that will be utilized is Sinovac as this is the most available and stable vaccine supply in the Philippines,” Guevara said.