Doctor: Why Pinoys Need Not Be Afraid Of Sinovac's '50% Efficacy Rate'

Sinovac was the top trending topic on Twitter, March 1, 2021, as soon as the Philippines delivered the first jab, setting into motion a long-delayed vaccination program against COVID-19.

Photo above shows one of the members of uniformed health personnel of Philippine National Police (PNP) getting the Sinovac COVID-19 vaccine during the first phase of vaccinations for health workers at Camp Crame in Quezon City on Monday.

Many tweets and social media posts questioned Sinovac's 50% efficacy rate, which pales compared rival vaccines from Pfizer (94%) and AstraZeneca (70%). All three have been certified for emergency use by Filipino authorities. The China-made drug was first to arrive.

What is Sinovac's efficacy rate?

Sinovac is the manufacturer behind the vaccine, CoronaVac, which has an efficacy rate of 50.4%. Efficacy rate is a measure of how effective a vaccine against a disease, in this case, COVID-19.

Efficacy rates are based on the performance of  the vaccine under ideal circumstances and controlled human trials. Vaccine trials take a representative sample to gauge its effects on the larger population.

Sinovac is 50% efficacious for mild cases, 78% efficacious for moderate cases, and 100% efficacious for severe cases, says Dr. Edsel Salvana, who heads the Institute of Molecular Biology and Biotechnology at the National Institute of Health. He is also part of the government's technical working group on vaccines, and he got the Sinovac vaccine on Monday.

Should an entire population catch the virus, say the common cold, and they all get vaccinated with a vaccine that is 50% efficacious, 50% of them will get colds, and the remaining 50% will not get sick. Of the 50% who will get sick, some of them could infect others.

But no one is likely to die, Salvana said. He adds those who do get sick will be less likely to infect others since they were inoculated.

Salvana based his explanation on his experience at the frontlines of the pandemic since it started last year. The NIH body that he heads was involved in processing RT-PCR or swab tests. He also said he had access to confidential papers.

Efficacy vs effectiveness of vaccine

According to the US National Library of Medicine, efficacy is about ideal and controlled circumstances. The effectiveness of a vaccine will be informed by the efficacy rate and performance in 'real-world' conditions.

Questions on Sinovac's efficacy stemmed primarily from its makers' refusal to immediately disclose their own human trials results.

So far, data on its effectiveness have been released by countries that used CoronaVac. It is up to 91.25% effective in Turkey's trials, but other, more robust trials in Brazil only demonstrated an efficacy rate of around 50.4%.

So far, only the Pfizer vaccine has had a real-world effectiveness that came close to the trial-based efficacy — 94% based on the Israel vaccine rollout.

Sinovac has 50% efficacy rate. Will it help fight COVID?

Salvana illustrated Sinovac's efficacy this way: It will reduce a lion into a cat.

It makes sense to get the most readily accessible vaccine to protect oneself now versus waiting for a higher efficacy vaccine and leaving oneself vulnerable to infection in the process, he said.

"The best vaccine is the vaccine that's in your arm," he said. "Tanggapin po natin kung anong bakuna nandyan dahil po ito ay makakasalba ng buhay."

Some healthcare workers have protested the use of Sinovac, saying they were promised the Pfizer vaccine. The first Sinovac vaccine was adminstered to Dr. Gerardo Legaspi, the Philippine General Hospital director.

"Yung leon po, ginagawa nating kuting. We are turning COVID-19 from a deadly disease that shut down the whole world into a common cold," he said.

"Wala pong takot sa sipon. Madami pong takot sa COVID. Yan ang ginagawa natin, tatanggalan natin ng pangil ang COVID para hindi na siya nakakatakot," he said.

Read more about COVID-19 vaccine:

WHO and CDC: Pregnant women can get COVID-19 vaccine

Immunologist answers: Should pregnant women get the COVID-19 vaccine

5 questions parents are asking about COVID-19 vaccine

Doctors: Huwag muna husgahan ang kahit anong COVID-19 vaccine   

This story originally appeared on Reportr.World. Edits have been made by the SmartParenting.com.ph editors.

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