A person infected with the coronavirus had to isolate themselves 10 days from the date of onset of symptoms or of confirmation of a positive test, according to Quebec. However, this period has since been revised and reduced to 5 days. In reality, there is no exact timeline or even a precise method that would indicate whether one is still contagious.
“It depends,” explains Hélène Carabin, professor of infectious disease epidemiology at the University of Montreal. “It depends on whether you are immunosuppressed, it depends on how quickly you get rid of the virus, it depends on whether the person is vaccinated. “
In general, the risk of contagion decreases significantly between 6 and 10 days after the onset of symptoms or confirmation of infection with a positive test. According to the US Centers for Disease Prevention and Control (CDC), the “statistical potential” to be contagious again becomes almost zero when reached on day 11.
The presence of symptoms can indicate that a person is contagious beyond this threshold, although this is not always the case. “Sometimes the symptoms can be a consequence of the immune response to the virus. So that could be the consequences of inflammation, when there is hardly any virus left, ”explains Hélène Carabin.
A positive test does not necessarily mean that the person is contagious, she continues, because a patient can carry copies of the virus in him which cannot infect another individual. “But the general rule is that when there are many [de virus], it’s much more likely to be infectious than if there aren’t many. “
In the face of so much uncertainty, judgment and prudence remain the best weapons of protection, she believes. “After 5 days, even if people return to work, it has to be done with strict precautions. […] And now is not the time to go and hug your loved ones, your grandparents. “
This text is taken from our newsletter “The Coronavirus Mail” of January 10, 2022. To subscribe, click here.