Mixing COVID-19 vaccine doses OK in certain situations —expert

Receiving a different COVID-19 vaccine brand for one's second dose can be done in certain circumstances, such as being allergic to the first brand, a vaccine expert said Wednesday.

Vaccine trialist and Dr. Lulu Bravo of the University of the Philippines College of Medicine made the observation in light of a study made by Combivacs—run by Spain’s state-backed Carlos III Health Institute—that showed that giving Pfizer-BioNTech to people who already received AstraZeneca for first dose is safe and effective.

“Mixing [vaccine brands] is not really recommended, because mag-iiba ang efficacy. Posible rin na mas mataas or mas mababa ang side effect; it remains to be seen. However, if indeed it should be done, isa na nga iyong allergy ka, hindi ka na puwede doon sa second dose,” Bravo said during the Laging Handa briefing.

[Mixing brands is not really recommended because it could affect the efficacy rate. It could also increase or decrease side effects; it remains to be seen. However, if indeed it should be done, one circumstance is if you have an allergic reaction from he first dose so you shouldn't get it again as a second dose.]

However, she added, doing so is generally safe.

“The way that we see vaccinology and the years that we have spent looking at the interchangeability, in general, it is safe. Because number one, allergic ka pala doon sa first dose, so hindi ka pwedeng magkaroon ng second dose. So you might have to be given another type of vaccine, right. Hindi masama iyon,” she added.

[If you turn out to be allergic to the first dose, you can't get the second dose.  So you might have to be given another type of vaccine, right. And that is not a bad thing.]

Bravo added that getting a different brand for the second dose is also allowed if the first brand is out of stock. It is also allowed if the vaccine recipient can confirm that the first dose did not produce the desired result.

“Number two, kung hindi na available ‘yung iyong first dose and it can happen. Halimbawa, nawalan ng stock and you don’t want to be exposed, puwede kang kumuha ng another vaccine. Number three, if you find out if the first vaccine that you got was not able to respond well, you might have to get another brand,” she said.

“Those are the conditions needed wherein it would be possible for you to get another brand,” she added. — BM, GMA News