South Korea to test sewage samples for COVID-19

South Korea this month will begin weekly tests of sewage produced by its major cities and towns to track the spread of COVID-19 and identify future waves.

Officials at the Korea Disease Control and Prevention Agency said Wednesday that wastewater surveillance will potentially provide a cheaper and more sustainable tool in the country's pandemic response. They say it could also improve the detection of other outbreaks, such as influenza, norovirus or drug-resistant bacteria.

According to the plans, health workers will conduct tests on sewage samples collected from 64 wastewater facilities nationwide at least once a week and regularly release analyses of the test results on its website.

KDCA said its recent trial runs with cities and provincial governments showed that the levels of pathogens found in sewage samples largely aligned with infection trends in those areas, confirming the value of testing water released from faucets, toilets and bathtubs. Similar tests have also been adopted in the United States.

South Korea had maintained a stringent COVID-19 response based on aggressive testing, contact tracing and quarantines during the earlier part of the pandemic, but has eased most of its virus controls since last year as the omicron variant's surge rendered those containment strategies irrelevant.

Government officials are also eager to revive a devastated service sector economy and attract more tourists. Their plans for wastewater testing are also an extension of their bend-but-not-break approach with COVID-19 that tolerates the coronavirus' spread among the broader population while concentrating medical resources to protect priority groups.

Lee Sang-won, KDCA's director of epidemiologic research, said wastewater surveillance could help the country's transition toward a more affordable virus monitoring regime.

South Korea's current system is still aimed at tracking every COVID-19 case by requiring hospitals to report all positive tests, an approach Lee described as expensive and laborious. He said health officials are considering an eventual switch to "sample-based surveillance," like they do with influenza monitoring, where only a certain number of designated hospitals register their cases.

"When that (transition) comes, we believe wastewater surveillance will function as a very effective tool" for providing complementary information on virus trends, Lee said during a briefing. "Another strength is that we can monitor various pathogens other than COVID-19."

While coronaviruses causing COVID-19 don't likely survive in water for long, Lee said the country's genetic testing methods would also be able to detect fragments of dead viruses.

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