MANILA — The Department of Health on Monday said that the country’s “omnibus guidelines” for COVID-19 testing and other measures will be delayed because the World Health Organization deemed antigen tests inappropriate for border screening.
The Philippine government earlier said that antigen testing, which is a faster although less accurate test for COVID-19, will be used for travelers entering and going around the Philippines.
“We met a bottleneck over the weekend when WHO issued their new guidelines for recommendation for the rapid antigen test,” Health Undersecretary Maria Rosario Vergeire said during a virtual briefing.
“Ang sabi kasi ng WHO recommendations, it is not advisable to use it sa mga borders for screening. Magkakaroon yan ng effect sa ginagawa nating guidelines,” she said.
(The WHO recommendation said it is not advisable to use it for border screening. This will have an effect on the guidelines we are crafting.)
The guidelines, which will also include protocols on contact tracing and isolation, were meant to be released this week. But, with the latest development, Vergeire said they will need to conduct a revision.
“Babaguhin natin ulit (We’ll have to change it). We will again undergo this series of consultations and most specifically, we need to present again to IATF (Inter-Agency Task Force) this revised version… But hopefully, if we can present tomorrow or Thursday, by early next week, we can issue these omnibus guidelines."
Vergeire said the WHO recommendation on antigen tests is understandable since the the COVID-19 pandemic is an “evolving situation” with new evidence and studies being published daily.
But she said they might still find a way to use antigen testing while following WHO guidelines, which they “take seriously.”
“We have recommended that this (antigen testing) be used sa mga borders din, sa mga incoming, sa mga tourists, kasi sandali lang s'ya, (and) accurate naman s'ya,” she said.
(We have recommended that this be used for borders, for tourists, because it is quick and accurate.)
In its September 11 guidance, the WHO said that antigen testing should not be used “for airport or border screening at points of entry.”
Other situations where antigen testing is not advisable are screening prior to blood donation, testing individuals without symptoms unless he/she is a contact, and if there are zero or only sporadic cases in the area.
The WHO said that antigen tests are “highly variable”, with sensitivity ranging from 0 to 94%, although specificity is high at around 97%.
Sensitivity refers to a test’s ability to detect SARS-CoV-2 or the true positive rate, while specificity refers to the test’s ability to identify those without the virus or the true negative rate. High sensitivity and specificity rates would ensure that the test won’t result in too many false positives and false negatives.
The WHO acknowledged that studies on antigen testing is limited, although it can be used in the following scenarios: as response to suspected outbreaks in remote settings and semi-closed communities where other tests are not immediately available, to support outbreak investigations, to monitor trends in disease incidence in communities, and in areas where there is widespread community transmission.
Clinical epidemiologist Dr. Leonila Dans of the University of the Philippine College of Medicine earlier told ABS-CBN News that more research is needed on antigen testing. A review that she did with other doctors showed that accuracy of antigen test results among asymptomatic individuals is very low.
Despite the WHO guidelines, Vergeire said they will still find a way to use antigen testing.
“Sometimes, there are processes na pwede mo naman gagawin na hindi mo s'ya i-o-oppose, pero pwede mo pa ring maipatupad. Katulad nitong sa antigen testing, may sinasabi na yung experts natin na pwede naman nating gawin pa rin para lang tayo sigurado,” she said.
(Sometimes, there are processes that you can still follow or not oppose, yet you can still implement your policy. Like on antigen testing, which our experts say can still be done just to be sure.)
Vergeire said they will be studying the WHO guidance to ensure that even if they implement antigen testing, it won’t result in a negative outcome.
“Titignan natin if we can still implement, in spite of these recommendation and international studies,” she said.
(We’ll see if we can implement, in spite of these recommendation and international studies.)
Experts have lamented in the past that indiscriminate testing is sometimes implemented just to show that something is being done. Dans said they still prefer the 14-day symptom-based test first, to check who will require further testing among possible pre-symptomatic or asymptomatic individuals.
The RT-PCR test is regarded as “gold standard” in screening individuals for COVID-19.