China May Have Prevented Over 700,000 COVID-19 Cases With Its Strict Control Measures to Stop Spread, Scientists Say

The tough measures taken by China to stop the spread of the new coronavirus in the first 50 days of the COVID-19 pandemic likely prevented 700,000 cases, according to a study.

After a mysterious new disease for which there is no treatment or vaccine began sickening people in the central Chinese city of Wuhan, Hubei province, in December 2019, officials took steps including quarantining millions of people to try to slow the rate of infection.

As shown in the Statista graphic below, the virus has since arrived on every continent except Antarctica. According to Johns Hopkins University, of the more than 877,400 total COVID-19 cases worldwide, 82,361 have been confirmed in China.

On January 23, China set its public health threat status to 1, its highest possible level. As part of the response, all cities closed their schools, isolated suspected and confirmed patients, disseminated information about the disease, and gave migrants health checks. The next day, travel from Hubei was banned in what is thought to be "the largest attempted cordon sanitaire in human history," the authors of the research published in the journal Science wrote. Overall, entertainment venues were closed and public gatherings banned in 220 cities, while in 136 cities intra-city transport was stopped, and travel within 219.

"The dispersal of COVID-19 from Wuhan was rapid. A total of 262 cities reported cases within 28 days," the scientists said.

As the COVID-19 virus is so new, how it is transmitted and whether its spread can be slowed is poorly understood, the team explained. More generally, while the spread of infectious disease has been "intensively studied," it's uncertain whether travel restrictions and social distancing measures prevent further transmission.

To investigate the effects of the measures taken between December 31, 2019 and February 19, 2020, the researchers looked at reported cases in every Chinese city; data on 4.3 million people travelling from Wuhan city between January 11 and a travel ban implemented there on January 23; and the timing and type of approaches taken in different cities. The 50-day-period of study included the 40 days of the Spring Festival holiday, and the 15 days prior and 25 following the Chinese Lunar New Year.

COVID-19 was found to arrive sooner in cities where more people had travelled from Wuhan, while the travel ban on that city was linked with a delay of 2.91 days on average of the disease arriving in other places, which gave people time to prepare.

The study revealed that cities which implemented any combination of control measures before the virus arrived had 33.3 percent fewer laboratory-confirmed cases in the first week of their outbreaks when compared with those which started later. Cities that stopped intra-city public transport and closed entertainment venues and banned public gatherings "and did so sooner, had fewer cases during the first week of their outbreaks."

Daily reports of new cases in Hubei peaked on February 5 at 3,156 confirmed cases and in all others on January 31. The team said: "The low level of peak incidence per capita, the early timing of the peak, and the subsequent decline in daily case reports, suggest that transmission control measures were not only associated with a delay in the growth of the epidemic, but also with a marked reduction in the number of cases."

Without the Wuhan travel ban or the national emergency response, there would have been 744,000 confirmed COVID-19 cases outside the city by February 19, the team found. With the Wuhan travel ban alone, the number would had dropped to 202,000. In comparison, the national emergency response alone would have prevented 199,000.

"Thus, neither of these interventions would, on their own, have reversed the rise in incidence by 19 February," they said. "But together and interactively, these control measures offer an explanation of why the rise in incidence was halted and reversed, limiting the number of confirmed cases reported to 29,839," which was "96 percent fewer than expected in the absence of interventions."

"In summary, this analysis shows that transmission control (non-pharmaceutical) measures initiated during Chinese Spring Festival holiday, including the unprecedented Wuhan city travel ban and the Level 1 national emergency response, were strongly associated with, though not necessarily the cause of, a delay in epidemic growth and a reduction in case numbers during the first 50 days of the COVID-19 epidemic in China," the authors argued.

Co-author Christopher Dye, visiting professor of zoology and visiting fellow at the Oxford Martin School, University of Oxford, said in a statement: "China's control measures appear to have worked by successfully breaking the chain of transmission—preventing contact between infectious and susceptible people."

There was, however, no evidence that stopping travel between cities or provinces cut the numbers of COVID-19 cases outside of Wuhan and Hubei, "perhaps because such travel bans were implemented as a response to, rather than in anticipation of, the arrival of COVID-19," the team said.

As many people haven't caught the new coronavirus, the team warned, it is likely "a large fraction of the Chinese population remains at risk of COVID-19; control measures may need to be reinstated, in some form, if there is a resurgence of transmission."

They said: "Despite all these measures, COVID-19 remains a danger in China."

Huaiyu Tian, associate professor of epidemiology at Beijing Normal University and study co-author, commented in a statement: "Given the small fraction of the Chinese population that has been infected, a much larger number of people remains at risk of COVID-19. We are acutely aware that resident or imported infections could lead to a resurgence of transmission."

Professor Stefan Elbe, director of the Centre for Global Health Policy at the University of Sussex who did not work on the study told Newsweek: "Until safe medicines and vaccines for new coronavirus become widely available, countries around the world must rely upon non-pharmaceutical public health interventions to save lives—like reducing the movement of people, prohibiting travel, closing schools and restricting public gatherings. These interventions are socially disruptive and economically devastating—making them politically very challenging for governments to implement and sustain. It is therefore critical to know that such interventions will be effective.

Elbe went on: "This study is an important attempt to gauge the early lessons from the first such restrictions introduced in Wuhan, China. The study's statistical and mathematical modelling of data from China following the first fifty days after the outbreak suggests that a combination of such non-pharmaceutical public health interventions was associated with a delay in epidemic growth and number of cases—with significant implications for China and the wider world."