PBB survey: Barangays without Covid-19 cases already infected

THE Project Balik Buhay (PBB) prevalence survey has found that barangays in the cities of Cebu, Mandaue and Lapu-Lapu City with no reported cases of the coronavirus disease (Covid-19) already had an infection.

“Based on our scaling model, we saw that these barangays (that) have no active cases based on the PCR (polymerase chain reaction) test, for ILI (influenza-like illness), SARI (severe acute respiratory infection),” said Department of Health Regional (DOH 7) Epidemiology and Surveillance Unit head Junji Zuasola during the press briefing aired live over the Facebook page of the Office of the Presidential Assistant for the Visayas (Opav).

“However, because of the study that we performed, we took samples from their residents, we found that even if they don’t have (Covid-19 cases), there are some residents that have IgM (active infection). They don’t have symptoms but they were exposed (to the virus); they had active exposure. Probably, they had infection,” Zuasola explained. “And at the same time, there are also some residents that already been exposed (to the virus) because they have IgG (past infection).”

“So that’s how the project was created, based on a hypothesis so that we can determine the enemy, especially among those that don’t show symptoms. That was the biggest challenge),” said DOH 7 regional director Jaime Bernadas on the PBB prevalence survey.

Identifying the virus

In Cebu City, 16 barangays had no reported Covid-19 case but got IgM positive rating ranging from 1.1 percent to 13.3 percent.

There were also barangays in the cities of Mandaue and Lapu-Lapu that had zero cases of Covid-19 but had individuals who tested IgM positive.

Some of these individuals who were positive of IgM and were tested using the polymerase chain reaction (PCR) test have been found to be Covid-19 positive, explained Mary Jean Loreche, DOH 7 chief pathologist.

As an example, Zuasola said there were six individuals in Barangay Pasil who tested positive for IgM but were asymptomatic. One person in Barangay Duljo in Cebu City, two in Barangay Maguikay in Mandaue City and eight in Lapu-Lapu City who were tested using the PCR were found to be Covid-19 positive.

“At the outset, our biggest challenge is the fight against Covid because the enemy is invisible. The only weapon used by our doctors and the health sector is our clerical acumen,” Dr. Bernadas said.

He added that the PCR test, which can identify the virus, and the rapid antibody test, which determines the body’s response to the virus, are the weapons against the invisible enemy.

Bernadas emphasized that with the prevalence survey, using the PCR and the rapid antibody test, the local government units (LGUs) were given the tools to fight against Covid-19.

Noting that 80 percent of infected individuals are asymptomatic, Dr. Bernadas said the prevalence survey would identify those who are actively infecting others in the barangays of the three cities.

Proposed lockdown

The prevalence survey showed that Cebu City has 2.2 percent per 100 household IgM prevalence while Mandaue City and Lapu-Lapu City has an IgM prevalence rate of 1.4 percent and 1.6 percent, respectively.

Zuasola said based on the findings of the survey, they proposed a sequential lockdown in some barangays to prevent a second wave of Covid-19 infection.

He added that the data collected from the survey would provide the LGUs with a guide on which communities will remain on lockdown and which ones will be unlocked.

However, he emphasized that the quarantine status should be highly dynamic depending on the results of the ILI-SARI surveillance.

The LGUs also have to actively pursue close contact tracing efforts, implementing the trace-isolate-swab-treat strategy, Zuasola said.

The prevalence survey will also help find old and new cases of Covid-19, he added.

The Opav initiated the PBB survey, in cooperation with the cities of Cebu, Mandaue and Lapu-Lapu, the business sector and the DOH. They all agreed that a mass testing be conducted in the three cities.

The PBB strategic mass testing was seen as a tool to help determine when to relax quarantine restrictions and allow the gradual resumption of businesses.

Opav Secretary Michael Lloyd Dino earlier explained that the strategic mass testing provides for a “wise, scientific, evidence-based, data-driven approach to help us rise above this pandemic.” (PR)