DOH: Signs of ‘herd immunity’ from COVID-19 seen in Cebu City

CEBU CITY, Cebu, Philippines — About a month after it “flattened the curve,” this capital city of Cebu province is showing signs that it may achieve herd immunity from the new coronavirus disease (COVID-19), according to the top official of the Department of Health (DOH) in Central Visayas.

Dr. Jaime Bernadas, the DOH regional director, cited a recent surveillance testing that showed 1,047 (47.48 percent) of 2,191 vendors at Carbon, the city’s biggest public market, developed IgG (immunoglobulin G), which, he described, as “an antibody produced by an exposed individual to SARS-CoV-2 (the virus causing COVID-19) as a means of defense against it.”

This indicated that they were asymptomatic and had already recovered from infection, he said.

“This is very significant because more and more people have now responded to the exposure of the virus, which means we are on the road to achieving herd immunity,” Bernadas said.Herd immunity, he said, could be achieved if 70 to 80 percent of the community had been exposed to the virus and developed immunity.

Health officials earlier conducted surveillance testing on vendors at Carbon after learning that many people who tested positive for the virus had visited the market.

More evidence

The testing involved a combination of rapid diagnostic test (RDT) and reverse transcription-polymerase chain reaction (RT-PCR) test, which remains to be the gold standard for confirmatory test of COVID-19.A total of 63 vendors yielded positive results during the RDT test, but when they underwent the RT-PCR test, only 33 samples turned out positive.

But Dr. Mary Jean Loreche, spokesperson for the DOH in the region, stressed that more evidence was needed to prove that the city was close to achieving herd immunity.

“Herd immunity is more likely to occur with vaccines. So for now, let’s adhere to the health standards that can prevent the transmission of the virus and at the same time protect us from getting sick,” she said in a separate interview.

“Based on the surveillance we conducted at Carbon market, we can safely say that the vendors [and] stall holders showed very low positivity rate, with IgG present, which could signify the past exposure or recoveries already,”Loreche added.

As of Nov. 1, Cebu City had recorded a total of 10,266 COVID-19 cases, but only 154 had been classified as active. It also listed 678 deaths and 9,434 recoveries.

Strict lockdown

On June 16, the city was placed under an enhanced community quarantine, the only local government outside Metro Manila covered by the strictest form of lockdown, due to a surge in the number of COVID-19 cases and the inability of local hospitals to effectively provide critical health-care assistance to patients.

This prompted the national government to send troopers of the police’s Special Action Force and policemen from other regions to enforce security and health protocols in the city.

President Duterte appointed Environment Secretary Roy Cimatu to oversee the government’s COVID-19 response in Cebu City, then considered the second epicenter of the virus after Metro Manila.

It took about two months, on Sept. 1, before the city’s status was downgraded to modified general community quarantine, the most relaxed form of quarantine, after the number of COVID-19 cases started to drop.