Molecular epidemiologist explains vaccine effect for the Philippines

| Written by Jo. Florendo B. Lontoc

Molecular epidemiologist Dr. Edsel Maurice Salvana was positive on the safety and benefit of the vaccines with emergency use authorizations (EUAs) in the Philippines’ fight against COVID-19, and on the manageability of COVID-19 cases in the country as the vaccines were being rolled out.

Speaking on February 23, 2021 as the resource person for the online forum, eKapihan, organized by the UP Alumni Association, Salvana warned, however, that the figures on both COVID-19 cases and those from clinical trials of the vaccines, on which he based his talk, were subject to change, as both were on-going events.

Vaccine effect

Salvana also said that based on clinical trials thus far, none of the vaccines available for emergency use can totally prevent viral transmission; but although they may not be able to “kill the lion”, they can “turn it into a kitten”, that is, prevent hospitalization from severe cases, thus easing the burden on the health care system, and prevent death.

Salvana compared Pfizer, Astra, and Sinovac, the three vaccines with EUAs in the country, and Moderna with each other. He noted that Sinovac, based on its Brazil “stress-test” on health workers, understandably lagged in terms of protecting recipients from developing symptoms; but it was still at par with Astra and Moderna in preventing by 100 percent deaths or cases that would necessitate hospitalization.


A screenshot of a slide from Dr. Edsel Maurice Salvana’s presentation at the UPAA’s eKapihan on February 23, 2021. Screenshot by Jo. Lontoc, UPMPRO.


“What is urgently needed? The vaccines to prevent deaths and severe disease among the vulnerable is the most important right now, until we can get to the point when we can block transmission and get herd immunity,” Salvana said. He referred to the frontliners, the elderly, and the chronically ill as the vulnerable populations.

“The data for children are not given for now. That doesn’t mean it’s not going to work [on them], but there are still clinical trials ongoing that can better define how we can use these vaccines,” Salvana pointed out. “Do not give for now,” he said, referring to children.

Salvana stressed that vaccine development for COVID-19 started 17 years ago from the original SARS outbreak.

He added that 208 million doses of COVID-19 vaccine had been given, “and not a single person [had] been proven to have died from it.” But caution must be taken on pregnant, immunocompromised, those with severe allergies, and the “frail elderly”. They should consult their doctors first.

Pandemic manageability

Salvana expressed optimism regarding the pandemic outlook in the Philippines. “If we stick to minimum health standards, our cases number will actually remain manageable.”


A screenshot of a slide from Dr. Edsel Maurice Salvana’s presentation at the UPAA’s eKapihan on February 23, 2021. Screenshot by Rad Agustin, UPMPRO.


To illustrate, he said there should have been a major surge at the end of January and the first couple of weeks of February following the last holidays, when a lot of people came out.

“Thankfully [the surge] didn’t happen which tells me people are starting to learn to live with the virus,” Salvana said. “All we really did see was a little bump up and it was outside Metro Manila.”

“Looking at what’s going on right now, the curve remains relatively flat, which makes me hopeful that we’re gonna be able to keep this trend until we get everyone vaccinated,” he concluded.

“The case fatality rate is better than worldwide—2 percent versus 3 percent. Our deaths are relatively low. We’re the 110th in the world in terms of deaths per million—109 per million compared to the US which has 15 times our death rate per million or 1,446 [per million], 1,294 [per million] in France,” Salvana said.

According to him, “The positivity rate [from tests] has been going down. It’s consistently about 5-6 percent.” Case management is also improving leading to higher survival rates, he said.

“Our number of cases is actually pretty good compared to other countries,” Salvana pointed out.

Because of these, he said the economy can remain open as the vaccines are being rolled out. If there are localized surges, he recommended proactive contact tracing and localized lockdowns.


A screenshot of a slide from Dr. Edsel Maurice Salvana’s presentation at the UPAA’s eKapihan on February 23, 2021. Screenshot by Rad Agustin, UPMPRO.


State of variants

He also stressed the importance of genetic surveillance being conducted by the UP Philippine Genome Center to track any new variant, contain it immediately, and make sure they are not spreading further.

Talking about the variants, feared for increased transmissibility: “We’re not sure of sustained community transmission yet. It seems like we caught them early.

“If you look at Israel, they went from 40 percent UK variant to 80 percent UK variant in one month. Now we have about 2 percent of our samples that we are looking at is UK variant. That hasn’t changed much. So it means like we’re doing a good job of keeping the UK variant under control.”

He noted that Pfizer and Moderna still had “enough antibody diversity to overcome the sustained mutation.”

Even so, he added, “There is no evidence right now that these mutations in isolation in these viruses that we see in the Philippines are actually increasing their virulence or if there’s gonna be any effect on vaccines.”

In his synthesis, Salvana said: “Now, with the vaccines that we have and more in the pipeline, and a faster roll-out, maybe in a year, we will have a semblance of normalcy.”

However, since there was not enough vaccine from just one producer, he recommended the use of all scientifically proven vaccines as soon as possible to save lives.

Salvana is Director of the Institute of Molecular Biology and Biotechnology of the UP Manila-National Institutes of Health and Adjunct Professor for Global Health of the University of Pittsburgh.


A screenshot of a slide from Dr. Edsel Maurice Salvana’s presentation at the UPAA’s eKapihan on February 23, 2021. Screenshot by Rad Agustin, UPMPRO.