‘Exactly what we expected:’ Scientists make sense of new COVID-19 cases in countries that had virus contained

May 12, 2020, 8:33 AM UTC

South Korea and China are rushing to contain new coronavirus outbreaks.

In China, the northeastern city of Shulan in Jilin Province is now in a ‘wartime battle’ against COVID-19, after a local cluster infected 12 people. The outbreak is traced to a laundry service worker at a local public security bureau, who didn’t have a recent history of travel or exposure to other known carriers, Chinese media reports. The city of Wuhan, the epicenter of the COVID-19 pandemic, also reported a cluster of six new confirmed cases on Monday, prompting authorities to lockdown the housing compound where the outbreak occurred.

In South Korea, a spike of 69 coronavirus cases over the weekend has prompted authorities to shut down all bars and restaurants in the capital of Seoul. At least 54 of the cases are tied to a man who patronized several bars and nightclubs in the city the previous weekend, according to South Korean authorities.

South Korea and China are considered coronavirus success stories, with each bringing new case tallies down to an average of a handful per day following bigger, initial outbreaks earlier this year. This made news of the new outbreaks especially devastating—to anxious citizens in each country and to a wider, global audience desperate for how-tos in taming the pathogen.

On Chinese social media, users have said they are ‘starting to panic‘ again because of the situation in Shulan. In South Korea, a wave of backlash has ensued against the country’s LGBT community, which is being discriminated against for its perceived role in instigating the new outbreak. The man suspected of spreading the virus did so while visiting several LGBT bars in Seoul.

For epidemiologists, however, the new outbreaks are not necessarily cause for broader concern or finger pointing. In fact, they consider new infections inevitable byproducts of a necessary opening-up process that will likely come in fits and starts.

“[New localized outbreaks] are exactly what we were expecting” when countries began to relax strict quarantine measures, says Ben Cowling, an epidemiologist at the University of Hong Kong. “The important thing is staying very alert to the possibility of infections and outbreaks and being ready to bring in public health measures if necessary.”

Lockdown, surveil, test

Both South Korea and China have responded aggressively to the fresh outbreaks.

In China, the city of Shulan has imposed a lockown on its roughly 700,000 residents since Monday. Non-essential businesses are closed, schools are shuttered, and public transportation and trains in and out of the city have stopped running. For city residents, only one person per household will be allowed to leave home each day for necessary purchases like groceries.

Before the recent outbreak, Shulan and surrounding areas had recorded only a handful of cases since January. The city closed down to a large extent in early February before resuming economic activities at the end of the month, according to the city government’s website.

In response to the new Wuhan infections, the city is reportedly planning to test all 11 million residents of the city within the next ten days. With the ambitious testing program, local officials seem especially eager to stamp out any potential outbreak in the city. Observers in China and abroad have widely criticized the city government for its initial response to the pandemic in December and January, and faulted Wuhan authorities for letting the virus get out of control.

Korean authorities, in addition to closing bars and nightclubs in Seoul, have embarked on an extensive contact-tracing and testing initiative to find people who might have contracted COVID-19 from Patient Zero of the new outbreak. As of Monday, Korean officials had tracked down and tested 4,000 people known to have visited one of the bars or clubs in question and are trying to contact 3,000 others who may have also gone to one of the establishments.

These measures speak to why both countries had earlier success containing larger outbreaks. South Korea managed to flatten its curve in just over a month, from mid February to late March, with a massive surveillance, contact-tracing, and testing campaign to identify suspected virus carriers. China had success in limiting the spread of COVID-19 in February by locking down large swaths of the country and isolating infected people away from their families.

The wider public should focus less on the occurrence of such second waves—they are bound to happen as public quarantine measures ease—but rather pay attention to how authorities act in response, says Cowling.

“We’ve learned that it’s possible to control local outbreaks,” he says. “The key element of that is very good surveillance and very good testing, so that we can pick up cases and outbreaks at an early stage, and stop them from developing into larger numbers of infections.”

China and South Korea have easy access to tracking technologies and testing supplies. Countries like the U.S., which reported over 18,000 new cases on Monday, may have more difficulty in preventing smaller outbreaks from spiraling into larger ones as the country eases quarantine restrictions because they’ve failed to ramp up testing and tracing to adequate levels, according to Cowling.

“The U.S. may have to relax some of their public health measures before [health officials would] like,” says Cowling. Ideally, relaxing quarantine measures would only happen once a country reaches high levels of testing and low daily case counts. However, the U.S. will probably have “difficulty achieving that” anytime soon, Cowling says, yet it’s eager to resume business as usual because of the dire economic fallout of shelter-in-place orders.

The new normal

In a Sunday address to South Korea about the new cases, President Moon Jae-in told citizens to keep up their guard, but he also sought quell fears of a larger second outbreak.

“We have now transitioned to a new normal in which safety precautions against the virus and daily lives can be simultaneously maintained,” he said.

Moon was referring act of balancing reopening economies with maintaining public health, a feat places like South Korea, China, Taiwan, and Hong Kong are trying to pull off after initially bringing new daily case counts down to near zero.

The new outbreaks and subsequent containment measures in China and South Korea speak to what Gabriel Leung, Cowling’s Hong Kong University colleague who advises the World Health Organization on infectious diseases, called the ‘suppress and lift’ strategy in New York Times op-ed in April.

“The restrictions must be lifted and reapplied, and lifted and reapplied, as long as it takes for the population at large to build up enough immunity to the virus,” he wrote.

When this ‘lift and suppress’ cycle ends is an open question, but Leung says more than half of the world’s population must become immune to COVID-19 in order to prevent resurgences of the disease. That can happen one of two ways: with a vaccine or if over 50% of all people get infected with the virus, recover, and develop immunity.

Let’s hope a vaccine arrives first.