Data from China has suggested that control measures quickly introduced in Wuhan may have greatly limited the spread of Covid-19.
While the coronavirus pandemic grips the world right now, China’s actions in the first 50 days of the outbreak may have delayed its spread outside of Wuhan by several days. New research published to Science has estimated that the control measures introduced in the initial weeks of the virus’ spread may have prevented more than 700,000 infections nationwide of Covid-19, the disease caused by the coronavirus.
“The number of confirmed cases in China by day 50 (19 February) of the epidemic, was around 30,000,” said Christopher Dye of the University of Oxford.
“Our analysis suggests that without the Wuhan travel ban and the national emergency response, there would have been more than 700,000 confirmed Covid-19 cases outside of Wuhan by that date. China’s control measures appear to have worked by successfully breaking the chain of transmission – preventing contact between infectious and susceptible people.”
The researchers combined case reports, human movement data and public health intervention information to track the spread of Covid-19, examining movements of 4.3m people who left Wuhan before the travel ban was introduced. They also looked at the types and timing of control measures implemented across the cities of China and the numbers of Covid-19 cases reported each day in every city.
‘An extraordinary reduction in movement’
Ottar Bjornstad, a professor of entomology and biology at Penn State, added: “Since the time period we studied included the Spring Festival holiday and Chinese Lunar New Year, we were able to compare patterns of travel into and out of Wuhan during the outbreak with cell phone data from two previous spring festivals.
“The analysis revealed an extraordinary reduction in movement following the travel ban of 23 January 2020. Based on this data, we could also calculate the likely reduction in Wuhan-associated cases in other cities across China.”
The restricted movement imposed in Wuhan helped more than 130 cities across China prepare for their own strategies, the researchers found, including the banning of public gatherings and closure of entertainment venues.
As a result, they reported 33pc fewer confirmed cases during the first week of their outbreaks than cities that did not implement a strategy.
However, Huaiyu Tian of Beijing Normal University warned that China is still very much at risk of further Covid-19 infections.
“Given the small fraction of the Chinese population that has been infected, a much larger number of people remain at risk of Covid-19,” said Huaiyu. “We are acutely aware that resident or imported infections could lead to a resurgence of transmission.”