An analysis of contact survey data from 636 participants in Wuhan and 557 participants in Shanghai, China, finds that social distancing alone, as implemented there during the outbreak, is sufficient to control the novel coronavirus disease COVID-19.
Intense non-pharmaceutical interventions were put in place in China to stop transmission of COVID-19.
As transmission intensifies in other countries, the interplay between age, contact patterns, social distancing, susceptibility to infection, and COVID-19 dynamics remains unclear.
To answer these questions, Dr. Hongjie Yu of Fudan University, Dr. Marco Ajelli of Bruno Kessler Foundation and their colleagues analyzed contact surveys data for Wuhan and Shanghai before and during the outbreak and contact tracing information from Hunan Province.
The results show that the average resident’s daily interpersonal contacts dropped 7- to 9-fold, from 14 and 20 people per day in Wuhan and Shanghai, respectively, to about two contacts per day in both locations by early February, after social distancing measures were put in place.
The survey data further show that between 78% and 94% of these contacts occurred at home, between fellow household members, during the social distancing period.
The researchers used the contact survey data, along with contact tracing data collected in the nearby province of Hunan, to build a mathematical model of COVID-19 transmission dynamics.
“Our results suggest that social distancing measures — and the resulting decrease in daily interpersonal contacts — led transmission rates to drop below epidemic levels in Wuhan and Shanghai,” the scientists said.
The model also estimated that, in China, children under the age of 15 are about 40% as susceptible to infection with SARS-CoV-2 as elderly people over the age of 64.
The model results further suggest that, while school closures helped to stem the rate of disease transmission in China — reducing the overall number of cases and the burden on the healthcare system there — such closures would not have been enough to quell the outbreak.
“It proved necessary to restrict residents’ human contact to others residing within their own household,” the study authors said.
The study was published in the journal Science.
Juanjuan Zhang et al. Changes in contact patterns shape the dynamics of the COVID-19 outbreak in China. Science, published online April 29, 2020; doi: 10.1126/science.abb8001
Source link: https://www.sci.news/medicine/social-distancing-08377.html