Herd immunity may happen faster with more effective COVID-19 vaccines: expert

Katrina Domingo, ABS-CBN News

Posted at Jun 25 2021 03:07 PM

Herd immunity may happen faster with more effective COVID-19 vaccines: expert 1
The Greenhills Theater in San Juan is converted into a vaccination site on June 1, 2021 as the city prepares to widen the category of those being vaccinated to A4, to include frontline workers in the private and public sector. Mark Demayo, ABS-CBN News

MANILA - A country needs to vaccinate fewer people against COVID-19 to attain herd immunity if it uses jabs that have higher efficacy ratings, a vaccine expert said Friday.

The statement comes after reports that countries relying on Chinese-made inoculants have been experiencing surges of COVID-19 cases despite vaccination of at least half of their population. 

"We have to establish that the higher efficacy vaccines you use, you need less percentage of people to vaccinate," said Dr. Rontgene Solante, member of the Philippine vaccine expert panel.

"If you're only using Sinovac, you need [to vaccinate] more. You need 80-90 [percent of the population vaccinated] kasi 'yung efficacy nila medyo mababa," he said in an online press conference.

A study from Brazil found that Sinovac can prevent severe cases of COVID-19 by 100 percent, but was only 51 percent effective in preventing mild to moderate cases of the disease, Solante said.

A separate study from Turkey showed that Sinovac was 91 percent effective in preventing mild to moderate cases of COVID-19, he said.

Clinical trials from other countries showed that Moderna and Sputnik V had 100-percent efficacy in preventing severe cases of COVID-19, and were 92 percent and 94 percent effective in preventing mild to moderate symptoms of the disease in patients.

AstraZeneca's jab is also 100 percent effective in preventing severe COVID-19 cases, but its protection for mild to moderate cases of the disease ranged between 67 and 80 percent, according to studies conducted in the United Kingdom, United States, Brazil, South Africa, Peru and Chile.

Prizer had a 90 percent chance of preventing severe cases of COVID-19, and was found to be at least 95 percent effective against mild and moderate cases.

"The efficacy will always be dependent on the population and the immune response of the patient," Solante said.

"In the clinical trials, controlled ang population... Kapag binigay mo 'yan sa ibang bansa... mayroong slight variability in the efficacy," he said.

The Philippines needs to vaccinate between 60 and 70 percent of its population since it is using various brands in its inoculation program against COVID-19, the vaccine expert said.

While the Philippines is also using AstraZeneca, Pfizer, Sinovac, and Sputnik V in its inoculation program, majority of the jabs available in the country are from the Chinese manufacturing giant.

Of the 16.2 million COVID-19 vaccine doses in the Philippines, about 11 million are from Sinovac, 2.5 million are from AstraZeneca, 2.4 million are from Pfizer, and 180,000 are Sputnik V jabs.

The Philippines earlier said that it has inked a deal with Pfizer for the purchase of 40 million COVID-19 vaccines, making it the government's biggest vaccine procurement by far.

The Philippines needs to vaccinate at least 58 million people to attain population protection against the disease that has infected 1.3 million individuals since last year.

As of June 22, 2.2 million Filipinos have been fully vaccinated against COVID-19, while another 6.6 million people have received their first dose.

"Forget the [COVID-19] variants at this point in time. Just have yourself fully vaccinated," he said.

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