US, WASHINGTON (ORDO NEWS) — As the new coronavirus spreads around the world, countries in which outbreaks are becoming more frequent are trying to find out whether China’s efforts to strictly isolate have helped control the crisis. Other countries now follow the example of China and restrict movement on their territory, while dozens of countries have restricted the entry of foreign tourists.
In mid-January, Chinese authorities introduced unprecedented measures to curb the spread of the virus, shutting down transport links to Wuhan, the epicenter of the epidemic, and 15 other cities in Hubei, home to over 60 million people. Flights were canceled and rail service was stopped, and roads were blocked.
Soon after, people in many Chinese cities were urged to stay home and go out only to buy food or go to the doctor. According to The New York Times, there were about 760 million people in home quarantine, or about half the country’s population.
It has already been two months since the prohibitions on movement in the country were introduced – some of them are still in force – and the number of new cases of the disease in the country is about a couple dozen per day, which is much less compared to thousands at the peak epidemics.
“These severe restrictions on the movement of people in the country have been very successful,” says Michael Osterholm, an infectious diseases scientist at the University of Minnesota in Minneapolis.
In a report released late last month, the World Health Organization congratulated China on its “unique and unprecedented health response [that] has helped stop the rise in disease.”
But the crucial question is which measures taken in China were most important to contain the spread of the virus, says Gabriel Leung, an infectious disease researcher at the University of Hong Kong. “The countries on whose territory the first wave [of infections] is now observed should know this,” he says.
Nature correspondents spoke with epidemiologists about whether isolation measures were really effective, whether calls to avoid crowds were enough, and what other countries could learn from China’s experience.
What happened after the introduction of strict isolation measures?
Scientists estimate that prior to the measures taken, each infected person transmitted the coronavirus to more than two other people, which created the conditions for the rapid spread of the virus.
According to the original models of the spread of the disease, which did not take into account measures to curb the spread of infection, it was estimated that 40% of the Chinese population, about 500 million people, would be infected with a virus called SARS-CoV2.
But between January 16 and 30, during the first seven days of isolation, the number of people infected with the virus from an infected person dropped to 1.05, Adam Kucharski concludes from the London School of Hygiene and Tropical Medicine, which models the spread of infectious diseases. “It was awesome,” he says.
In China, the number of new infections per day probably reached its peak on January 25, just two days after Wuhan was isolated.
According to WHO, as of March 16, about 81 thousand cases of the disease were registered in China. Some scientists believe that many cases of the disease were not recorded there, either because the symptoms were not severe enough and people did not seek medical help, or because tests were not performed. But it seems obvious that the measures taken during this time have indeed been effective, says Christopher Dye, an epidemiologist at the University of Oxford (UK). “Even if the number of cases was 20 or 40 times greater, which seems unlikely, measures to curb the spread of infection worked,” says Dai.
Could the measures taken by China be more effective?
According to epidemiologists, the activities undertaken by China on a gigantic scale had one obvious flaw: they started too late. In the first weeks after the outbreak in December and January, Wuhan authorities took time and did not report cases of a mysterious infection, which is why measures to contain it were delayed, says Howard Markel from the University of Michigan at Ann Arbor, who studies health problems. “And the fact that China did not immediately take action is probably the cause of the spread of the virus around the world,” Markel says.
A simulation model created by new disease researchers from the University of Southampton (UK) Lai Shengjie and Andrew Tatem shows that if China had introduced its measures to prevent the spread of the virus a week earlier, it would have prevented 67% of all cases in the country. The introduction of these measures three weeks earlier, that is, from the beginning of January, would reduce the number of infections to 5% of the total.
Data from other cities also indicate the effectiveness of immediate action. According to the data published by the Data on measures to control the spread of the virus, taken in 296 Chinese cities, in settlements in which public transport was suspended before the first case of COVID-19 was detected, entertainment facilities were closed and a ban on public events was introduced , the number of cases of infection was 37% less than in cities where no such measures were taken.
Was China’s travel ban really effective?
The results of numerous analytical studies of air travel show that the ban on leaving Hubei Province, as a result of which people could not leave the province on airplanes, trains or cars, allowed to slow the spread of the virus, but not for long. According to an article published March 6 in Science magazine by scientists from Italy, China and the United States, Wuhan’s isolation slowed the spread of the disease to other cities in China by about four days.
These scientists found that isolation measures and travel bans had a longer lasting effect at the international level, which helped prevent the spread of the virus from China to other countries in four out of five cases within two to three weeks. But then, people traveling from other cities transferred the virus to other cities in the world, causing new outbreaks of the virus infection. According to the model created by scientists, even if the number of trips is reduced by 90%, it is possible to slow down the spread of infection only slightly if no additional measures are taken.
Because travel bans can slow down the spread of this disease alone, bans must be introduced in a way that inspires confidence in the authorities, says Justin Lessler, epidemiologist at Johns Hopkins University in Baltimore. “If you force people to lie or try to circumvent the ban, these measures will be ineffective,” he says.
Currently, travel restrictions have introduced dozens of countries in Europe, America, Africa and Asia.
However, WHO warns against such bans by arguing that they are usually ineffective in preventing the spread of infection and can divert resources from other more effective measures and create barriers to assistance and technical support, as well as harm to many industries.
What lessons should other countries learn?
Using their model, Tatem and Lai evaluate how early detection of the disease and the measures taken by China to isolate the foci of infection, the resulting reduction in the number of contacts between people and the prohibition of long-distance travel in the country together affect the decrease in the spread of the virus. Together, these measures prevented a 67-fold increase in the number of cases – and if they had not been taken, almost eight million cases would have been reported by the end of February.
The effect of reducing the number of contacts between people was significant in itself. Using data on the location of mobile phones obtained with the help of Chinese Internet giant Baidu, scientists found a sharp decrease in the number of movements of people, which, according to them, means a significant reduction in the number of personal contacts. According to scientists, if not for this reduction in the number of contacts, then in late February the number of people infected with the virus would be about 2.6 times more.
But the most important factor in reducing the incidence of COVID-19 was early detection and isolation. If not for these activities, the number of infections in China would be five times more than at the end of February. “When setting priorities, the most important thing is early diagnosis and isolation,” says Tatem.
Early diagnosis yielded positive results in Singapore. According to Vernon Lee of the Singapore Ministry of Health, who heads the Outbreak Response Team, Singapore is one of the countries where it was quicker to identify infected people because doctors were warned of “mysterious pneumonia.” As soon as the first cases of the disease appeared in Singapore, doctors quickly identified and isolated the cases and began to track their contacts, says Lee.
There are still fewer than 250 COVID-19 infections in the country, and it did not have to impose the same strict restrictions on movement that were imposed in China. Some activities were canceled, people infected with COVID-19 were quarantined, and temperature screening and other community outreach activities were being conducted, Lee said. “But life goes on,” he says.
The effectiveness of quarantine school closures in China is unknown. According to a preliminary publication of research data on the spread of the COVID-19 virus in Shenzhen, children are just as susceptible as adults, but it is not yet clear whether children (many of whom have no symptoms of the disease) can spread the virus. “This will be critical to assessing the effectiveness of quarantine school closures,” says Lelsler, co-author of the study.
Can we say that the number of cases of COVID virus infection in China is declining?
In China, the number of new cases of COVID-19 has plummeted, but some fear that once the country has completely weakened its efforts to prevent the spread of infection, the spread of the virus may resume. He may even come back to China from countries where the epidemic of the disease has just begun. And since the measures taken by China helped protect a large number of people from infection, many of them do not have immunity against the virus, says Liang.
China does not destroy the virus, but suppresses its spread, says Osterholm. According to him, in order to find out what China has achieved and what it has not achieved with its measures to limit the movement of people, the world will have to wait about two months when China will somehow return to normal life.
In all likelihood, there is a fierce discussion in China about when to weaken isolation measures, says Roy Anderson, an epidemiologist at Imperial College London. He suggests that when they are canceled, a second wave of new infections may begin.
At some point, isolation measures will have to be lifted, and authorities should remind people to maintain social distance and hygiene, Anderson says. “What matters is not so much the measures taken by the government as our own actions,” he says.
Contact us: [email protected]
The article is written and prepared by our foreign editors from different countries around the world – material edited and published by Ordo News staff in our US newsroom press.