Getting five or six Covid-19 shots can run the risk of losing the vaccines' overall effectiveness, or worse, might render the person ineligible to get upgraded or multivalent vaccines against variants of concern (VOC) in the future.
In a public briefing of the Department of Health (DOH), Dr. Edsel Salvana said that it's really important to follow instructions provided in the emergency use authorization (EUA) of the vaccine which is usually issued by the Food and Drug Administration (FDA) because these are studied.
"Lalong-lalo na yung mga additional doses na fourth, fifth dose, wala pa po tayong sapat na ebidensya kung ano yung effects nito long-term (Most especially the fourth, fifth dose, we don't have enough evidence as to its long-term effects)," he added.
Salvana explained that there are vaccines that when multiple times on short intervals can lower its effectiveness as a whole causing an "antibody exhaustion". This will continually lower vaccine effectiveness according to him, regardless what will be injected moving forward.
He urged the public not to experiment and follow instructions regarding vaccines.
On the other hand, Health Undersecretary Maria Rosario Vergeire said that out of the more than 30 million people that they are waiting for to get booster shots, some may have already received it through a third or even a fourth dose.
She assured that Covid-19 vaccines being administered in the country are safe as long as the proper guidelines are followed. Beyond that, she stated that they can no longer ensure its safety and effectiveness against Covid-19.