Covid-19 and social distancing: the effects of the lockdown in China

In Italy, the so-called “Phase 2” began on May 4, which triggered a slow and gradual return to normal. But it is not yet the time to lower the attention threshold and forget the rules that in recent weeks have constantly accompanied us in the fight against the new Coronavirus, one above all that of social distancing. And the measures of social distancing seem to have allowed China to stop the spread of COVID-19. Only the results of the study by an international team led by the Bruno Kessler Foundation of Trento and the Fudan University of Shanghai published in the journal Science supported it.

The research. China was the first country to face the Coronavirus emergency and was able to control its spread. This led scholars to conduct an analysis to identify the factors that led to the reduction of the transmission in China. The study showed a 7-8-fold reduction in the number of people contacted per day during the lockdown period in Wuhan and Shanghai and also highlighted that children are about 4 times less susceptible to infection than the elderly. By using mathematical models, the authors estimated that this reduction in contacts alone is sufficient to contain the spread of COVID-19.
The study analyzed the responses of about 2,000 inhabitants of Wuhan and Shanghai who were asked to indicate their daily contacts before and during the Chinese lockdown, thus allowing to estimate the change in the number and type of contact made by people during the implementation of social distancing measures.

“The number of contacts – explains Marco Ajelli, of the FBK, who coordinated the study – has fallen from 14-19 per day before the start of the epidemic to about 2 contacts per day, the great majority of which with their family members . Furthermore, by analyzing the data on over 7,000 contacts from 136 cases of COVID-19, we were able to estimate that children have a risk of becoming infected about 3 times lower than adults and 4 times lower than the elderly. Through the use of computer simulation models, we were then able to show how the social distancing policy adopted in China was able to control the spread of the infection. ”

“Italy”, Stefano Merler of FBK underlines, “has followed China in adopting a rigorous policy of social distancing which is now giving the hoped for results, with a recent reduction in the number of new cases registered, hospitalizations and deaths caused by the coronavirus. This study helps us understand the impact of this kind of policy and the importance of each person doing their part in limiting the number of contacts. The fact that children are less susceptible to infection, which is very positive in itself, must not deceive about their possible role in the transmission of SARV-COV-2. In fact, they are also the ones who have the highest number of social contacts, especially in school “.