Countries may need to impose new lockdowns every 3 months until a coronavirus vaccine is available, an expert says

Getty ImagesA man crosses an empty highway road on February 3, 2020 in Wuhan.

In late January, China put 60 million residents on lockdown to slow the spread of the coronavirus in its hardest-hit region, the Hubei province.

Residents were not allowed out of their homes except to go to grocery stores or pharmacies. Planes, trains, and buses into and out of the city were shut down, and public transit and private car travel were stopped.

Nearly two months later, as outbreaks grow in new epicenters around the world, other countries are following suit. Italian residents are under a full lockdown – domestic and international travel are banned, nonessential stores are closed. In the country’s hard-hit Northern regions, even jogging and taking walks are not allowed. Spain has also told residents to stay inside, with exceptions for buying food, some essential work, and medical emergencies.

Some US states, including California, Ohio, and Louisiana, have issued “shelter-in-place” or “stay-at-home” orders.

After two months of strict quarantine measures, China’s coronavirus epidemic may finally be ending – the country reported no new local infections for the first time last Thursday. But China could face a major resurgence of the virus when it lifts its lockdowns, according to Dr. Ben Cowling, an epidemiologist at Hong Kong University who researches influenza transmission and control measures.

A boomerang effect could occur, Cowling said, as residents emerge from their homes, go to work, take their children to school, and go shopping. There are two ways the virus could take hold again. First, a small number of Chinese residents who were under lockdown might still have the virus when restrictions lift but not know they’re sick. Those people could then spread it, starting a new wave of infection. Second, international travellers could bring the virus back into the country.

Once cases begin to rise again, authorities will most likely have to mandate social distancing once again – a second lockdown.

“What happened in Wuhan could happen repeatedly to a city,” Cowling told Business Insider.

‘I don’t see the long-term plan’

“Lockdown” isn’t a technical term used by public-health officials, but it can refer to mandatory quarantines, recommendations to stay at home, closures of certain types of businesses, or bans on events and gatherings.

Cowling foresees on-again, off-again lockdowns on the horizon for places that have already instituted quarantines and shelter-in-place measures.

That’s because once residents emerge from lockdown and start to be in close contact once again, the virus will be able to more easily circulate among people who haven’t contracted it yet – which could be between 30-60% of the population. Some case studies suggest people can get the virus more than once.

If asymptomatic patients and those with extremely mild cases don’t get tested, some may not know they have COVID-19 and may spread it. The virus’ incubation period is, on average, five days, and more than 97% of patients test positive within 12 days. Still, the incubation period can last longer than 14 days in 1% of patients, one study suggested.

“They can shut down for a month, but then when they reopen, they’re still going to have an epidemic starting again, and I don’t see the long-term plan for those locations,” Cowling said. “Are they going to just cycle? Just down one month in every three months?”

Epidemiologists project that between 40-70% of the population will get the coronavirus by the time the pandemic subsides.

“I think this idea … that if you close schools and shut restaurants for a couple of weeks, you solve the problem and get back to normal life – that’s not what’s going to happen,” Adam Kucharski, an epidemiologist at the London School of Hygiene & Tropical Medicine, told Vox. “The main message that isn’t getting across to a lot of people is just how long we might be in this for.”

The pandemic won’t really end until most of the population has developed immunity to the disease or until there’s a vaccine.

A boomerang effect

Already, China, Taiwan, Singapore, and South Korea – which seem to be on the tail end of their outbreaks – are seeing new cases once again, but these are being imported. On Thursday, China confirmed it had no new domestic cases in the country for the first time since the outbreak began in December. But it reported 34 new cases in travellers who recently returned to China, mainly from Europe.

Imported cases outnumbered domestic transmissions for five consecutive days from March 13-18, according to Reuters.

Two children wear face masks to protect against the spread of the coronavirus and watch dumpling making of Din Tai Fung at a department store in Taipei, Taiwan, Saturday, March 7, 2020. (AP Photo Chiang Ying ying)Chiang Ying-ying/AP PhotoTwo children wear face masks to protect against the spread of the coronavirus and watch dumpling making in Taipei, Taiwan, March 7, 2020.

Similarly, South Korea – which has seen lower and lower numbers of new domestic cases for the past few weeks, thanks to widespread testing and isolation efforts – reported 44 new travel-related infections at the beginning of last week.

And in Taiwan on Wednesday, there were 23 new cases of the coronavirus, 19 of which were imported, Taiwan’s health minister, Chen Shih-chung, announced. He added that most of the imported cases were from Europe.

Chen predicted a second wave of outbreak on Monday: “We held firm to block the first wave of infection, but a new wave is coming, so everyone should cooperate with disease prevention efforts,” he said.

Waves of coronavirus

Chinese scientists and health experts have downplayed the possibility of another domestic wave of coronavirus infections.

“For me, a second outbreak (of coronavirus), a domestic outbreak in China, wouldn’t be a great concern,” Cao Wei, deputy director of the Department of Infectious Diseases at the Peking Union Medical College Hospital, told Reuters.

But experts have pointed out that the 1918 flu pandemic killed more than 50 million people in three waves. The second was the deadliest.

Cowling thinks the coronavirus will be continuously imported and exported around the world – and that lockdowns will be difficult to keep reissuing.

“It’s going to circulate around the world for the foreseeable future,” he said.

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