Shanghai quick to contain coronavirus outbreak

Meticulous measures prove effective

If everything goes according to plan, lockdowns at a residential neighborhood and a major hospital in downtown Shanghai will end on Feb 4 after two weeks.

Zhang Wenhong, head of the city's COVID-19 clinical experts team, said controlling the outbreak in Shanghai, which has a population of more than 24 million, was "like catching mice in a porcelain shop".

During the latest outbreak, the city took steps to ensure its vibrant business activity continued and that people's lives were not disrupted unnecessarily.

In the past week, new COVID-19 cases were reported in Shanghai only on Saturday, with both of them discovered during testing of people linked to confirmed cases.

A hospital employee who was among medical workers tested on Jan 20 was confirmed to have COVID-19 the following day.

A total of 18 locally transmitted cases have been reported during the new outbreak in the city.

The Shanghai Municipal Health Commission said more than 55,000 people linked to the confirmed cases were screened and placed in quarantine as necessary.

No widespread nucleic acid testing was conducted on the public in the city.

Zhang said, "Our refined management measures help us detect a case among crowds in the city, identify those possibly infected before they develop symptoms, and contain the virus.

"These factors are particularly significant, as COVID-19 cases that emerge from time to time will become a new normal."

More than 100 million COVID-19 cases have been reported worldwide. Local infections in China last month totaled 2,016, the most since March last year.

Li Qiang, Shanghai's Party secretary, said the pandemic situation is still complicated and everyone must constantly remain vigilant, detect any shortcomings and check for loopholes.

Defining boundaries

Late on Jan 20, the Shanghai Cancer Center Affiliated with Fudan University reported a "suspicious result "for an outsourced logistics worker at the facility during nucleic acid testing conducted on staff members.

Immediately after receiving this information in a phone call, Zhang and other health officials, experts and pandemic control workers rushed to a local disease control and prevention center, where they worked throughout the night.

Tracing and screening the logistics worker's close contacts began straight after the suspicious test result was obtained, along with an epidemiological investigation.

"If we had started this work just one minute later, there may have been one more route in which the virus could have spread, which would need to be tracked, but getting on top of the situation immediately enabled us to take the initiative in pandemic prevention and control," Zhang said.

Wu Fan, a member of the team of public health experts involved in Shanghai's COVID-19 prevention and control efforts, said disease control professionals worked for 15 consecutive hours on Jan 20 and 21.

Based on the logistics worker's contact history, they conducted in-depth analysis to define a virus transmission chain.

"They analyzed the possible extent of the chain, the public areas involved and the number of people who might have been infected," Wu said.

She said the team then investigated links in the transmission chain. More than 30 close contacts of the patient were identified and placed under hotel quarantine that night, and 2,817 people who were in close contact with those quarantined were traced.

Wu said, "Community workers in different areas of the city raced against time to knock on people's doors before dawn, telling them not to leave home to prevent the possibility of the virus spreading."

Disease prevention workers checked areas frequented by those confirmed with COVID-19, including their workplaces, over the past 14 days.

They checked individuals' routes to determine whether their activities in different locations could have contaminated these areas or spread the virus to others.

They took into account whether those infected were wearing a face mask, the time they spent in a particular area, and whether they touched anything or spoke to anybody.

Wu said these factors determined the level of risk at a venue.

She added that those infected were encouraged to go through their digital consumption records, shopping receipts, and phone call and online chat records in order to remind themselves where they had been and those they met during the past two weeks.

"An individual's recollection of seemingly unimportant things is very important for us to trace possible interaction, and helps us decide what steps to take next," she said.

Pan Hao, deputy head of Shanghai's front-line COVID-19 working team, said that if an infected person took a taxi, the team members assessed the level of risk posed to the cab driver.

Factors considered include whether the passenger sat in the front or back of the taxi, whether the windows were open, if the person wore a mask correctly throughout the trip, and whether he or she paid digitally or with cash.

Sun Xiaodong, deputy director of the Shanghai Municipal Center for Disease Control and Prevention, said the routes taken by those infected with the virus and people suspected of carrying it need to be traced meticulously.

"Such timely, accurate and scientific epidemiological investigation work gives us confidence that we have screened all chains of virus transmission. As a result, we can precisely determine the number of people who need to be screened, instead of imposing mass testing," he said.

Gaining experience

The orderly and accurate work showed that those newly confirmed with COVID-19 were among the virus transmission chains already discovered in the epidemiological investigation.

The first three new cases in Shanghai, reported on Jan 21, involved two hospital logistics workers who were among staff members regularly screened for the virus, and a friend of one of the employees.

Twelve of the other 15 cases involved close contacts of those confirmed with the disease, and the remaining three were found through screening.

Shanghai is aiming to become one of the world's safest cities for public health by 2025.

Zhang, who is also director of the Department of Infectious Diseases at Huashan Hospital Affiliated with Fudan University, called for a powerful, multi-layered team of public health professionals to be set up from grassroots to city level.

Such a refined management structure would help in coping with future outbreaks, whether they are caused by coronavirus or a new source, Zhang added.