Expert: No time to be choosy with vaccine

EVEN with the mass inoculation for the coronavirus disease 2019 (Covid-19) finally underway, the government still has not fully convinced majority of the people to get their shots.

Standing in the way are prevailing perceptions about the risks of getting vaccinated and the efficacy of some vaccines.

But a member of the Department of Science and Technology’s Vaccine Expert Panel warned in an online interview with The Manila Times that this was not the time to be choosy when it came to a Covid-19 vaccine because the virus had already mutated.

Dr. Nina Gloriani, a microbiologist, believes that any of the three vaccines approved for use in the country is capable of providing protection against infection.

Given the green light for emergency use in the Philippines are Pfizer

and BioNTech tozinameran’s Cominarty, AstraZeneca’s AZD1222, and Sinovac Biotech’s CoronaVac.

CoronaVac has the lowest efficacy rate at 61 percent, while Cominarty has the highest at 95 percent.

For Gloriani, the detection of Covid-19 variants and mutations in parts of the country means that the government must waste no time in immunizing as many people as it can.

The Department of Health plans to vaccinate at least 70 million people before the end of this year to achieve herd immunity, the percentage of the population that has to be vaccinated to reach an acceptable threshold of protection against the virus.

“Para sa akin, kung ano ang mauna d’yan, kung high-risk ka for exposure to Covid, you take the vaccine, a 50-percent efficacy is better than zero. Hindi tayo pwedeng mag-wait nang matagal, dahil ang variants nandito na (For me, whatever vaccine is the first to be rolled out and if you have a high-risk exposure to Covid, you have to take it, as a 50-percent efficacy is better than zero; and we cannot wait for too long since the variants are already here),” Gloriani said.

The emergence of variants will affect the efficacy of the vaccines, although manufacturers were modifying their vaccine formulations to create booster shots against the mutations, she said.

To prevent mutations from affecting vaccine efficacy, the public must continue to practice health precautions such as wearing face masks and face shields, physical distancing and continued hygiene.

“Kung ang tao, nag-iingat mabuti, wala nang pupuntahan ang virus kasi ang virus, habang may malilipatan na buhay na cells, dadami s’ya at dadami; at habang siya ay nagre-replicate, mataas ang mutation nya kaya dapat mapigil ang transmission (If people are really being careful, the virus will not be able to transfer itself. So long as it moves to a living cell, it will multiply until it replicates and create a mutation. So, it is imperative that we prevent transmission),” Gloriani said.

She added that relying solely on a vaccine’s efficacy rate could be misleading, since the rate could differ widely during clinical trials for a specific sector such as health care workers, adults aged 18 to 59 years old, or senior citizens.

“If you test the vaccine in a general population where the exposure to Covid is lower, tataas ang efficacy mo, maiiba iyun,” she explained.

Such was the case for the CoronaVac, which posted a 50.4-percent efficacy among health care workers in a clinical trial in Brazil.

“At the time of the clinical trial, ang taas ng kaso ng Covid cases sa Brazil…if you are talking about 10,000 na binigyan ng bakuna — kalahati placebo — puro health care workers ‘yun and in a situation na mataas ang cases, mataas din ang possibility or probability na magkaka-Covid sila so mataas ‘yung gan’ung scenario (the Covid cases in Brazil were already high…so if you are talking about the 10,000 people who were given shots — half of which were placebo — all of them were health care workers who were in situations where there prevalent cases, they had a high probability of being infected with Covid, that scenario is hugely [expected]),” Gloriani said.

The 50-percent efficacy threshold for Covid vaccines set by the World Health Organization was based on the different attack rates of the virus across the globe.

In the end, what counts most is the protection the vaccine provides against the most severe infection.

“With a pandemic vaccine, hindi natin expect na mapo-protektahan ang lahat, pati mild, moderate, severe, but what we are after, na ma-protektahan against the severe form of the disease, kasi ayaw natin may mamatay, may ma-critically ill kasi ‘yung health care system, papanik din ang ating resources doon (we still cannot expect to protect everyone, including those with mild, moderate and severe cases, but what we are after is to protect them against the severe form of the disease because we do not want health workers to die or be critically ill and to experience a strain in our health care resources),” Gloriani said.