Some Delta variant cases who were earlier tagged as recoveries have once again tested positive for COVID-19, the Department of Health (DOH) said Monday.
Health Undersecretary Maria Rosario Vergeire said nine local Delta variant cases and five returning overseas Filipinos who were tagged as recovered were asked to undergo a repeat quarantine and COVID-19 test.
“Among the initial results that we have received, meron po sa kanilang nag-positive pa rin [some of them still tested positive],” she said in a Palace briefing.
“Chine-check natin ang (We are checking the) Ct values and they will remain to be isolated until they turn negative after 14 days,” she added.
The Ct value of a sample will determine whether it is eligible for genome sequencing.
Vergeire explained that under updated protocols, individuals who recover after testing positive for a variant of concern will be asked to undergo a fresh round of quarantine and COVID-19 testing.
“They shall remain in isolation while awaiting results. Those whose RT-PCR is negative, already asymptomatic, and have completed the minimum 10-day isolation may be discharged from isolation,” she told reporters.
“Contact tracing done shall be reviewed to identify RT-PCR positive close contacts whose samples may be eligible for sequencing. Testing with RT-PCR was advised by our experts at [the] end of 14-day quarantine,” she added.
Last year, Vergeire explained that a recovered patient may test positive for COVID-19 if the PCR machine picks up remnants of the coronavirus.
Genome sequencing efforts
Meanwhile, Vergeire said efforts are underway to expand the country’s capacity for whole genome sequencing since only 1% of COVID-19 cases are sequenced, lower than the ideal rate of 5%.
“‘Pag dumating na po ‘yung extraction machines na binili ng PGC (Philippine Genome Center), mado-doble na po ang kapasidad natin to 1,500 [samples] per week,” she said.
(Once the extraction machines purchased by the Philippine Genome Center arrive, we can double our capacity to 1,500 samples per week.)
Vergeire noted, however, that the purchase of the machines may take some time as it is still undergoing procurement processes.
She added that expanded whole genome sequencing will also be done through sub-national laboratories and University of the Philippines networks.
Vergeire also admitted that there may be undetected variant cases due to the country’s limited genome sequencing capacity.
“The possibility is always there,” she said when asked about the matter.
The health official explained that samples for sequencing are only taken from areas with a high number of COVID-19 cases.
“We do purposive sampling. We are not covering the entirety of all of those turning positivity because of our capacity,” she said.
“So kapag ‘yan ang ating objective, we cannot say that we are underreporting because the samples that are purposively collected ay nakokolekta po at nate-test natin. Pero nandiyan po tayo, we recognize that fact na talagang kailangan mag-expand tayo.”
(So if that is our objective we cannot say that we are underreporting because the samples that are purposively collected are tested. But we recognize that we need to expand.)
The Philippines has logged 1,481 Alpha cases, 1,685 Beta cases, and two Gamma cases as of July 15.
The country has also recorded a total of 35 Delta variant cases, three of whom have died. —KBK, GMA News