MANILA - Mixing and matching different COVID-19 vaccine brands in one person may produce mild to moderate adverse events, a vaccine expert said Friday.
A study from the United Kingdom - involving 830 adult volunteers - showed that those jabbed with AstraZeneca for their first dose and Pfizer for their second dose tend to develop "more adverse effects," said Dr. Nina Gloriani, head of the Philippines' vaccine expert panel.
"Not serious, but mild to moderate like headaches and muscle pain were reported more frequently when different vaccine doses were combined," she said in an online forum.
"But these were short-lived and there were no other safety concerns," she said.
A separate study from Spain showed that mixing 2 COVID-19 vaccine brands in one person is "found to be safe," Gloriani said, noting that the study also made use of AstraZeneca and Pfizer jabs.
"Neutralizing antibodies were found to be significantly high after the combination," she said.
The Philippines is set to begin its own research on the mixing and matching of vaccines in Filipinos next month, Department of Science and Technology Secretary Fortunato dela Peña earlier said.
The study which will have 1,200 participants - will focus on mixing Sinovac with other brands as the country has a steady supply of the former vaccine, he said.
Gloriani said the Philippines' P100-million study will be called "interchangeability" of COVID-19 vaccines, but protocols surrounding the series of tests are still being finalized.
"We cannot help [but do] it kasi 'yung iba talagang hindi makukuha yung same brand and we have all possible situations," she said.
The research seeks to answer questions on the vaccines' effects as determined by ethnicity and how long their efficacy would last on Filipinos, DOST Undersecretary Rowena Guevara said in a press conference earlier this week.
The national government hopes to inoculate at least 58 million Filipinos by the end of 2021 to attain herd immunity against the disease that has infected at least 1.1 million people in the country since last year.
So far, the Philippines has fully vaccinated 1 million people, while 3.46 others have received their first dose of COVID-19 vaccine.