Covid-19: asymptomatic people would be four times less contagious
A person positive for coronavirus but asymptomatic would be far less contagious than a person with symptoms, reports a large study in Singapore.
In terms of contagion, whether or not you have symptoms of the Sars-CoV-2 coronavirus infection obviously changes a lot.
In a new study, published Dec. 18 in The Lancet, researchers report finding nearly four times more contagion for people with Covid-19 and symptomatic than for asymptomatic.
To measure the relative contagion of people with Covid-19 based on their symptoms and HIV status, the researchers looked at all the people who completed their isolation quarantine between August 1 and October 11, 2020.
A total of 628 people with Covid-19 were included in this analysis, as well as 3,790 “contact” people, who were isolated. Of these 3,790 contact cases, 89, or 2%, had Covid-19. And of these, 50 people, or 56%, were placed in isolation after contact with an asymptomatic person, while 39 people (44%) were declared contact with a symptomatic case.
Then, by verifying the data, the researchers calculated that the risk of becoming infected was 3.85 times greater for contact with symptomatic people than for people who had been in close contact with someone who was positive for the coronavirus but asymptomatic.
"Our results suggest that people with asymptomatic Covid-19 are infectious but may be less infectious than symptomatic cases," the researchers said. While it is important to maintain the broadest possible search for contact cases, the authors believe that in case of lack of resources, it is possible to limit ourselves to looking only for contact cases of symptomatic people, as these are the most contagious. Especially since people with Covid-19 symptoms are also easier to identify and more likely to be tested.
Note that these results are in line with the findings of another study, conducted by researchers from Imperial College London (UK). This had reported a risk of contamination of 12.8% for cases of contact with symptomatic people, compared to 3.5% for people who have been in contact with an asymptomatic person.