Chambers propose mass screening with RST to curb CoVid-19 spread

© RITM Researchers at the Research Institute of Tropical Medicine prepare to load reagents into a real-time PCR machine as they check their testing kits for the Zika virus on Wednesday, February 3.

The Philippine Chamber of Commerce and Industry today endorsed to President Rodrigo Duterte a resolution from its affiliate chambers in Mindanao urging the ramping up of mass screening of possible COVID-19 cases in the country through the adoption of the Rapid Serologic Test (RST) as a surveillance tool.

In its letter to the president coursed through Executive Secretary Salvador C. Medialdea dated today, PCCI President Amb. Benedicto V. Yujuico also requested the Food and Drug Administration (FDA) to grant Emergency Use Authority to the application for registration of verifiable suppliers of RST kits, and to set up “PCR Sub-National Reference Laboratories” in all regions of Mindanao.

 “We urgently need to check the health of our communities and this is only possible using mass testing in the field. Having statistics of sick patients in the hospital is just too late,” said Ma. Teresa R. Alegrio, PCCI area vice president for Mindanao.

“We need to know actual cases in the field even before they become symptomatic or no longer symptomatic (unknowingly healed) to make targeted decisions before they even get to hospitals,” she added.

PCCI is advocating the immediate rollout of the mass screening program using RST by local government units in partnership with national agencies, Philippine Red Cross and other NGOs starting with all PUIs awaiting access to PCR testing, all PUMs, vulnerable persons within the vicinity of a cluster of Covid-19 outbreak, and among front liners in the hospital and in the field. Persons who test positive from RST mass screening should also be required to undergo priority confirmatory testing by PCR.

The chambers are also requesting the Food and Drug Administration Philippines (FDA) to grant Emergency Use Authority to approve the applications for registration of verifiable suppliers of RST Kits that already underwent the registration process with their respective FDAs in their country of origin.

Not the least, PCCI also supports the call of many LGUs and regional bodies to set up  “sub-national reference labs” in all regions of Mindanao in addition to the four already being set up in the San Lazaro Hospital in Manila, the Baguio General Hospital & Medical Center in Benguet, Vicente Sotto Memorial Medical Center in Cebu City, and Southern Philippines Medical Center in Davao City.

The Western Visayas Medical Center and the Bicol Public Health Laboratory are also being prepared for testing. 

In addition to the University of the Philippines – National Institutes of Health (UP-NIH), five private hospitals are also being assessed by the DOH and the World Health Organization as possible extension laboratories. 

These are the molecular biology laboratories of St. Luke’s Medical Center – Global City, Makati Medical Center, The Medical City, St. Luke’s Medical Center – Quezon City and Chinese General Hospital.

Medical workers at Kaiser Permanente French Campus test a patient for COVID-19 at a drive-thru testing facility in San Francisco, California on March 12. (AFP, Josh Edelson)

Indonesian Experience

A week ago, Indonesian President Joko Widodo ordered the rollout of rapid tests for COVID-19 across the country in a bid to accelerate detection of the disease.

Rapid tests are easier to perform than regular polymerase chain reaction (PCR) tests and can detect COVID-19 cases quicker.

Since rapid tests like the RST only require blood serum as a sample, these can be conducted by most health laboratories across the country enabling mass testing in COVID-19 hit areas to be performed quickly.

It is easier to implement than the regular tests like PCR, which must be performed in level two biosafety laboratories, since they involved the sampling of nasal fluids or larynx substances which contain the virus as main specimens.

Since rapid tests are easier to perform, Indonesia expects more people to be tested and sent to hospitals if found positive. To anticipate a rise in confirmed cases, Jokowi called for hospitals to set up health protocols for handling those who had performed the test.

The West Java administration conducts COVID-19 rapid tests for 300 medical workers & staff of Hasan Sadikin Hospital at Anggrek Polyclinic, Bandung, Indonesia on March 25. (West Java public relations)

PCR too slow to determine virus spread

Although PCR (polymerase chain reaction) is a tried and tested method to confirm COVID-19 infection in PUIs and PUMs, it does not give a true picture of the spread of the infection in a community due to the length of time it takes to confirm a test, now worsened by the backlog at the Research Institute for Tropical Medicine (RITM) due to the sheer volume of samples, the shortage of testing kits to meet the demand, and the extended time to send samples to RITM due to the lockdown of the national transport network.

RITM is the sole testing facility in the country at present since the four additional regional centers are not yet ready to conduct tests.

The US Center for Disease Control & Prevention is distributing 1.1 million PCR test kits in a bid to curb the COVID-19 pandemic in the US. (techcrunch.com)

Indirect Method

“RST is an excellent tool to check the presence of antibodies naturally produced by the human body as a defense mechanism to fight the presence of a destructive foreign body, e.g. the SARS-CoV2 /COVID-19 virus,” said Roderico Biaco, PCCI-X Regional Governor. “It is an indirect method of detecting the presence of the virus (the infection), unlike the PCR test which detects the actual virus itself.”

“Each has innate limitations, serve different functions, but should be used together to complement each other in combating the global pandemic,” Biaco noted.

Biaco said needs a better surveillance tool that is affordable, reasonably accurate and reliable, easily deployable in the field with minimal technical skill (no need special laboratory with HVAC and negative room pressure, etc), and safer (no need to transport live virus samples).

It is also important to note that our field operatives and front liners know that they have fair access to the testing themselves to boost their morale, he added.

“Furthermore, we can map out (geo tag) the existence of the spread of the virus using GIS (geospatial information system) and updating the GIS database is faster using RST,” Biaco stressed.

“This is critical in planning and executing decisions in the field. We need to analyze faster patterns and trends the virus spreading in the community to make proactive policies and timely decisions.”

Genexpert system with Xpert Xpress SARS-CoV-2 test.

RST vs. PCR explained

In the early stage of infection( first 5-6 days), a true positive person may be tested negative by RST (false negative) because his body may not yet have produced enough antibodies that can be detected by RST. RST is not the proper tool to monitor the ongoing infection, that is the role of PCR, he explained.

On the other hand, science journals are saying that the infection starts in the lungs and the virus may not still be present in nasal tracts or sputum 1-5 days after exposure for the PCR test to detect possibly yielding a false negative also.

PCR also cannot detect the virus if the person has already completely healed from the disease.

How RST buys time

The IgM and IgG antibodies that are specific to the COVID-19 virus may take around 5-6 days after exposure for the body to produce enough antibodies detectable by RST.

At that point, the infected person may start showing symptoms. Most healthy persons are expected to show mild reaction to the virus and may even be asymptomatic, but his immune system already produces antibodies combating the virus.

Upon successfully fighting the virus, the infected person gets rid of the virus in his system, but the antibodies may remain in his body for several days.

In this event, PCR test can no longer determine the presence of the virus nor diagnose if the person went through the infection in the first place in the absence of prior testing. However, in this case, RST can determine with a high degree of accuracy a past infection of the person from COVID-19.

“This is a critical function of RST not doable by PCR. RST is an excellent tool to diagnose the general health of the community, while PCR for the individual patient,” Bioco said.

In the event of intercepting by RST a healthy person that went through the disease undetected, we have the opportunity to conduct contact retracing, isolate, contain and mitigate and stop the cluster from breaking out (that otherwise PCR screening alone cannot do).

Reports also claim that most of the transmission of the virus is by asymptomatic persons. Thus, it is important to cast a wider net to catch the virus, and do it fast.

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