70% Of People Infected With COVID-19 Do Not Infect Anyone - Study

70% of people infected with COVID-19 do not infect anyone - study

A group of Hong Kong epidemiologists indicates that "super-spreaders" are responsible for the vast majority of SARS-CoV-2 coronavirus infections. The study is being prepared for peer review.

Photo: kian zhang / Unsplash

Most of the new cases of COVID-19 are the result of infection of people by so-called super-spreaders. In a study by Hong Kong epidemiologists, only 20% of those infected with SARS-CoV-2 were responsible for 80% of new infections. The preprint of the scientific work is published on the researchsquare.com service. The study has not yet been peer-reviewed.

An interesting finding of scientists was that 70% of infected people do not transmit the virus further to other people. The vast majority of infections occur as a result of episodes of super-spread: when one person transmits the virus to a large number of people in closed rooms or in transport.

“Superproliferation cases happen more often than we expected, in more cases than we have been able to explain by now. The frequency of super-proliferation is beyond our current understanding,”commented Ben Cowling, co-author of the study, on the new data for Business Insider.

Cowling added that we now know that preventing superproliferation will benefit a huge number of people.

For their study, Cowling et al analyzed over 1,000 COVID-19 cases in Hong Kong between April 23 and 28. According to them, super-spreading was the main mode of transmission of the virus in the city.

More than half of the infections in Hong Kong itself were associated with just six episodes of super-spread of infection. Infection took place at public events and in public places: in a temple, at a wedding and in bars. 20% of cases were the source of 80% of infections. The remaining 20% ​​of infections were associated with another 10% of those infected.

“Social interactions produce a much higher number of secondary infections compared to exposure at home and at work,” the authors conclude.

Business Insider points out that other epidemiological studies have previously shown similar results. In 2011, in the International Journal of Infectious Diseases, scientists spoke of the "20 to 80" rule: 20% of those infected are responsible for 80% of infections in many infectious diseases.