Vaccine expert: In pandemic, ‘no protection worse than partial protection’

A vaccine expert on Friday said that in the midst of a severe pandemic, a vaccine with an efficacy rate of at least 50% will offer "partial protection" that will be better than no protection at all.

But Dr. Lulu Bravo, executive director of Philippine Foundation for Vaccination, stressed that the incidence rate of COVID-19 in a specific place is just as important a consideration as the safety and efficacy of a vaccine.

Brazilian researchers said the Chinese pharmaceutical company Sinovac's COVID-19 vaccine has been found to have an efficacy of 50.4%. The Philippines has secured some 25 million doses of Sinovac's product.

At a Senate hearing, Senate President Vicente Sotto III asked Bravo whether she would administer a vaccine with an efficacy rate of only 50%.

"That 50% efficacy was actually set by the WHO (World Health Organization) long before, in the beginning of the pandemic. They even said that an efficacy of 50-70% would be already acceptable in the midst of a pandemic because these efficacy rates are actually needed to be put in place when you have a severe pandemic," Bravo said. 

"When the incidence is so high that a 50% efficacy would really be good enough so we have that kind of protection, because no protection of course is worse than a partial protection, so I guess that would be a good efficacy rate should you be able to get that vaccine," she added.

But she explained that the Philippines has many vaccine experts and that no single opinion may be enough, considering various incidence rates of COVID-19 in different places.

"It really depends on various factors, it's not just safety and efficacy, but the incidence of COVID in that place that will matter most," she said.

The expert also explained that efficacy is not just one number but a range.

She said that in the case of the Pfizer vaccine, its 94% efficacy means that "severe infection" is prevented by 94% to 100%, but that it is not yet known if the vaccine prevents transmission or just the symptoms.

"From preventing all kinds of infection, or is it just preventing the severe infection and the hospitalization of a certain vaccine, and that will be seen and determined by the way the clinical trial is done," she said.

"It's not easy to say, sir, that one figure will be enough to say whether you have prevention of transmission, prevention of hospitalization, or prevention of severe symptoms," she said. — RSJ, GMA News