Vietnam Coronavirus research re-defines contact tracing strategy as Sri Lanka expands Covid-19 testing

ECONOMYNEXT – Sri Lanka has expanded Coronavirus tests leading to several new patients being found officials said, as Vietnam researchers have shown how to close gaps in current Covid-19 contact investigations by tracing up to three generations of contacts of a confirmed case and testing two.

Some Coronavirus patients do not show symptoms.

“Recently we started testing samples of persons who have come into contact with confirmed patients,” Anil Jasinghe head of Sri Lanka’s Health Service said.

“In the future we hope to increase this number to find out whether there are more infected persons.”

Sri Lanka’s military chief Shavendra Silva said 10 persons were discovered in Puttalam, after 19 likely contacts who had been closely associated with a patient was tested.

Sri Lanka found one infected person in the First Wave arrivals from China, had has found 158 infections after Wave II started from European countries that did not block or quarantine ‘healthy’ arrivals from China, or trace contacts during Wave I.

Sri Lanka started contact tracing early along with Vietnam, before community transmission became widespread, and are making progress in preventing wider community transmissions.

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The disease is going viral in most countries and they are at stages where contact tracing no longer makes sense.

Researchers from Vietnam, where tens of thousands had been quarantined and tested during Wave II after successfully halting community transmission from the Wave I from China, have identified gaps in current process in an article to be published in the news issue of the International Journal of Tuberculosis and Lung Disease (IJTLD), released online under a fast-tracking process.

Read: Adapting a TB contact investigation strategy for COVID-19

As of April 02, Vietnam had confirmed 239 Coronavirus patients, 90 had recovered and been released. None had died up to April 03.

Among the recovered is a 72 year old Wave I patient from China, with a history of complications.

Vietnam had tested 75,219 and excluded 17,700 persons, after multiple tests.

The authors from the Woolcock Institute of Medical Research, Hanoi, Viet Nam; Sydney School of Medicine, Faculty of Medicine and Health, The University of Sydney, Australia, supported by others in Laos say at least three generations of contacts have to be traced and two tested to successfully kill community transmission.

T A Nguyen, Q N Cuong, A L T Kim, T N Huong, H N Nguyen, G J Fox, G B Marks, say once a patient had been identified (F0), the next generation should be tested and another two generations traced.

“First, three generations of contact (F) with COVID-19 cases should be traced to offer timely testing if the previous contact generation is found positive,” they wrote.

“This algorithm starts with the first generation (F1) who are close contacts of the index case (F0).

“All F1 contacts should be tested for SARS-CoV-2 regardless of symptom presentation.

“F1 individuals who are asymptomatic or have two negative tests 24 hours apart should be quarantined for 14 days.”

“F2 contacts should self-isolate at home and be monitored by public health units. If F1 tests positive, we recommend that F3 contacts should also be identified.

“When the previous F becomes positive, the next one will be informed to follow the contact management procedure.”

Quarantine persons should also be tested twice before being released, the researchers say.

“Inappropriate quarantine discharge could occur among patients who have an initial negative test for SARS-CoV-2 and may subsequently test positive,” they said.

Sri Lanka had not been testing everyone in quarantine like in Vietnam, but asks every person released from quarantine to self-quarantine for another 14 days at home.

Like Sri Lanka, Vietnam started to quarantine Wave II arrivals from selected countries starting from Italy, and later made quarantine mandatory for all arrivals when it became evident that it had spread to all countries that had not been tracing contacts in Wave I.

Thousands of Vietnamese who live or study abroad also returned home, including a one person who returned in an executive jet from UK and had since recovered, were quarantined.

Vietnam welcomed 18 million tourists in 2019 and 1.9 million tourists in December 2019.

Vietnam had 73,925 persons in home quarantine or surgical lockdown over 38,000 in military run quarantine centres free of charge or fee paying hotels (premium quarantine) before all arrivals were stopped when the country ran out of space. (Colombo/Apr04/2020)

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