Date: April 1, 2020
By: Asian Scientist Newsroom
Tough control measures taken by China in the first 50 days of the epidemic may have prevented more than 700,000 infections, a study finds.
AsianScientist (Apr. 1, 2020) – Tough control measures taken by China during the first 50 days of the COVID-19 epidemic, such as travel restrictions imposed on the city of Wuhan, may have prevented more than 700,000 infections across the country, finds a new study published in the journal Science.
“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,” said Professor Christopher Dye of the University of Oxford, UK, a senior author on the paper.
“China’s control measures appear to have worked by successfully breaking the chain of transmission—preventing contact between infectious and susceptible people,” he added.
The international team, which included researchers from the UK, the US and China, used a unique combination of case reports, human movement data and public health intervention information to investigate the spread and control of COVID-19. They examined the movements of 4.3 million people out of Wuhan before the travel ban, 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.
Using novel data streams such as cell phone mobility data, the researchers tracked movement over a period that included the Spring Festival holiday and Chinese Lunar New Year. By comparing patterns of travel into and out of Wuhan against two previous spring festivals, their analysis revealed an extraordinary reduction in movement following the travel ban of January 23, 2020.
“This delay provided extra time to prepare for the arrival of COVID-19 in more than 130 cities,” said Associate Professor Tian Huaiyu, an epidemiologist based at Beijing Normal University, and a senior author on the paper.
Among other actions, these cities banned public gatherings, closed entertainment venues and suspended public transport. As a result, they reported 33 percent fewer confirmed cases during the first week of their outbreaks than cities that did not implement a Level 1 Response.
While the control measures taken thus far have reduced the number of COVID-19 infections to very low levels, China is still at risk from community spread and imported cases, the authors said. They also noted that SARS-CoV-2 may establish as a human endemic globally in the years to come and lead to seasonal epidemics.
“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,” Tian said.
The article can be found at: Tian et al. (2020) An Investigation of Transmission Control Measures During the First 50 Days of the COVID-19 Epidemic in China.