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Sri Lanka sees Covid infections rise among quarantine workers amid calls for change in testing strategy

COMMUNITY SCREENING: Staff of a company in Tan Thuan Export Processing Zone in HCMC lining up for tests by Vietnam’s Centres for Disease Control. Source/Touitre Online.

ECONOMYNEXT – Sri Lanka has not taken decision to allow private sector labs to conduct Coronavirus tests officials said, while a philosophy against voluntary or precautionary community screening of those at risk had also not changed according to what health official say.

Sri Lanka had had discussion with private hospitals about using their capacity to expand testing, the head of Sri Lanka’s Health Service Anil Jasinghe said on Friday but no decision was taken to allow them to conduct tests.

“We had a discussion with private hospitals about using their capacity for tests in case we need it,” Jasinghe told a domestic television station.

“But the higher education ministry (which has universities with labs) had offered their PCR machines which will expand capacity.”

Sri Lanka initially wanted all symptomatic patients to turn up in state hospitals, which observers agree is a good strategy.

Private hospitals were allowed to test, provided the patient was admitted. However there are no drive-in tests for aymptomatic persons working in high risk areas.

As long as curfews are in place, contact tracers could passively wait for symptomatic persons to turn up.

The person from Suduwella and Colombo’s Bandaranaike Pura tuned up during curfew.

Zero Community Screening

But when curfews are lifted under the current strategy private sector companies would have to operate without the ability to test drivers, cleaning staff and any other workers who meet many people who wanted to cut risks.

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Advocata Institute, a Colombo-based think tank, had asked authorities to allow persons in high risk areas to be get a test, as there was zero chance of an asymptomatic person who is not linked to a known index case from being discovered by authorities.

The current plan discovering new patients is too dependent on symptomatic patients turning up in hospital, and there was zero change of asymptomatic persons in high risk areas being discovered the think tank pointed out.

“The current contact tracing strategy has a serious flaw in that it is too dependent on symptomatic cases and there is no way to detect an infected index case that is asymptomatic,” the think tank said.

“Voluntary testing, random testing of people in high-risk areas will increase the chance of asymptomatic index cases and members of clusters being discovered.

“Once curfew is lifted, the front office staff of any institution including airports, quarantine workers, cleaning staff, people working in economic centres, and drivers may be exposed to higher risks.

“Those in driving/delivery related jobs, in particular, would also be in a position to spread the disease faster and to a greater area.”

This week Sri Lanka was shaken a large cluster developed at a Navy base among sailors involved in quarantine work who were not screened under the current testing philosophy.

One of the sailors who was on leave had travelled to many areas, jumping on food trucks in some cases, authorities said. The sailor was discovered because he developed symptoms and went to hospital.

His un-screened colleagues were not symptomatic up to that point. On the first day they were screened 29 turned up positive.

Anti-Screening Philosophy

A senior health official in the state testing system said that even for a blood test to be conducted when there is an ‘indication’ and cannot be just taken because a patient wanted it.

“You cannot conduct a PCR test because you think there is a risk,” he said explaining the philosophy of the health officials behind their opposition to precautionary tests.

“There has to be an indication like a symptom or a link with some person to conduct a test. You can’t conduct a blood, or a sugar test just because you want it.”

However those calling for testing of high risk persons are doing so on the grounds of probability and an assumption that no one is infallible in tracing contacts and there could be a few persons out there with the disease, perhaps.

If curfews are lifted they would no longer be any protection from spreading, and persons who meet many people on different locations could get infected and become carriers.

“That it just fear,” the health official said. “That is not science. You cannot ask for a test based on fear. We do not conduct tests like some other country. We may also change what the WHO says.”

Observers say there could be a weak understanding of probability among medical professionals.

A community screening of high risk areas would raise the chance of discovering asymptomatic persons from the current zero to a positive number.

Diagnostic vs Screening

Senior health officials had earlier said on television they were opposed to a PCR test being used for ‘screening’ because it was a ‘diagnostic’ test by definition.

Unlike Vietnam, Sri Lanka did not initially test contacts of index cases (to discover whether the next level and been infected and act fast to isolate the next two levels) or those that were released from quarantine.

Sri Lanka Coronavirus contact tracing gaps plugged as incubation of SARS-Cov-2 suspected to top 20 days

Senior health officials had earlier said on television they were opposed to a PCR test being used for ‘screening’ because it was a ‘diagnostic’ test by definition.

The strategy had since been changed and now contacts and released persons are tested.

At the moment only PCR tests are the only available remedy for ‘screening’, with blood tests for antibodies, especially those made in China being shown to be unreliable in many countries and returned.

The anti-test community screening philosophy seemed to be based on a belief that there could be no infected persons that the contact tracers missed.

PCR tests also have the advantage of being showing virus genes before anti-bodies develop, according to medical professionals.

Vietnam, the most successful country in containing the epidemic had widely used PCR tests for screening.

Vietnam authorities had also used PCR tests on discharged patients and found that they also run the risk of turning positive.

On April 25, Vietnam went on a renewed community testing drive after the discovery of two new cases, after the lapse of 08 days. Like airline passengers inter-district truck drivers are also required to take tests. (Colombo/April25/2020)