Differences in regional outbreaks and responses mean the timeline in China doesn't extrapolate directly to other epicenters of the pandemic around the world, said lead researcher Kiesha Prem of the London School of Hygiene & Tropical Medicine.
Although the results can not be directly applied to other countries (because the researchers calculations are specific to China), "we think one thing probably applies everywhere: physical distancing measures are very useful, and we need to carefully adjust their lifting to avoid subsequent waves of infection when workers and school children return to their normal routine", study co-author Yang Liu, a research fellow at the London School of Hygiene & Tropical Medicine said in the statement.
"But we think one thing probably applies everywhere: physical distancing measures are very useful, and we need to carefully adjust their lifting to avoid subsequent waves of infection when workers and school children return to their normal routine", he said.
The scientists also said given the large uncertainties around how many people an individual with the virus is likely to infect, and how long a person is infected on average, the true impact of relaxing physical distancing measures on the ongoing COVID-19 epidemic can not be precisely predicted. "But if they relax the restrictions gradually, this is likely to both delay and flatten the peak", Prem said. In one scenario, schools and workplaces were closed just for the Lunar New Year holidays, which occurred in mid-January in China. In another scenario, extreme social distancing measures were put in place after the holidays so that schools remained closed and only 10% of the workforce (including health care staff and police) remained active.
These closures, they said, were then extended to reduce person-to-person contact and prevent the spread of SARS-CoV-2.
The study used mathematical modeling to simulate either extending or relaxing school and workplace closures in Wuhan, a city of 11 million people whose name has become synonymous with the coronavirus for much of the world.
China's long lockdown in Wuhan may have bought the country months of time before a feared second wave of coronavirus cases peaks, according to a study with implications for how long other nations may have to maintain similar restrictions.
The team also predicted the impact of lifting control measures.
The results showed that closing schools and workplaces just for the Lunar holiday would have had little effect on the progression of the outbreak.
"However, the modelled effects of physical distancing measures vary by the duration of infectiousness and the role school children have in the epidemic".
On further analysis, the scientists suggested that physical distancing measures may be most effective if the staggered return to work commences at the beginning of April - potentially reducing the median number of new infections by 24 per cent up to the end of 2020, and delaying a second peak until October.
Results of the study will not look exactly the same in another country "because the population structure and the way people mix will be different", said Dr Yang Liu of London School of Hygiene & Tropical Medicine.