Secretary Carlito Galvez Jr., vaccine czar and chief implementer of the Naational Task Force (NTF) Against COVID-19, disclosed Wednesday, Sept. 1, that he supports the administration of a third dose or "booster shot" of vaccine against the coronavirus disease to the most vulnerable sectors, particularly healthcare workers and people with comorbidities.

Galvez said that he sees no problem with the recommendation of some medical experts that booster shots should be given to healthcare workers who were inoculated with CoronaVac vaccine made by Chinese manufacturer Sinovac Biotech as its efficacy against the Delta variant, now the dominant strain in the country, wanes after six months.

"If I'm the one to be asked, we have to give full protection to our healthcare workers and comorbidities," he said in a virtual guesting at the Kapihan sa Manila Bay.

Dr. Rontgene Solante, an infectious disease specialist, said last Monday that there may be a need for a booster shot for individuals who got the Sinovac shot as its efficacy drops against the Delta variant after six months.

He shared a recent study in Thailand which showed that the protection of Sinovac-injected individuals went down to 48.33 percent from 93.33 percent against the Delta variant six months after receiving their second dose.

However, Galvez said the NTF is still awaiting the recommendation of the World Health Organization and Vaccine Expert Panel (VEP) as to when is the most appropriate time to give booster shots.

He explained that there is a "moral question" in giving booster shots since majority of the population is not yet vaccinated with their first dose.

"There are studies na lahat ng vaccines magwe-wane ang efficacy (the efficacy of all vaccines wane) at a certain period of time. But 'yong sa boosters, hinihintay po natin ang advice ng WHO at VEP (But as forthe boosters, we are waiting for the advice of WHO and VEP)," the vaccine czar said.

"Kailangan unahin ang iba na wala pang first dose (We need to prioritize those who have not yet received their first dose)," he added.

As of Aug. 31, a total of 13,958,418 Filipinos have been fully vaccinated while 19,747,877 have received their first dose. The government aims to vaccinate 77 million or 70 percent of the total 110 million population by the end of 2021 so the country can achieve herd immunity.

Some countries such as the United States and Israel have already started giving booster shots to its population after they vaccinated majority of their population.

Last Aug. 27, Department of Health (DOH) Undersecretary Maria Rosario Vergeire said the DOH was not yet recommending the administration of booster shots pending the results of studies whether it actually improves an individual's protection against the emerging variants.

As for the WHO, it said the administration of booster shots in the context of the current global supply constraints "will exacerbate inequalities by driving up demand and consuming scarce supply" while priority populations in some countries have not even received their first dose.