Covid-19: after how many days is a patient no longer contagious?
Since the start of the health crisis, there have been many unknowns about the coronavirus. Health authorities do not yet know how long a patient is contagious, but researchers have made estimates.
The World Health Organization (WHO) considers that the incubation time of the coronavirus is 3 to 5 days, but in some patients it can reach up to 14 days. This period characterizes the time that elapses between infection and the appearance of the first symptoms of the disease. During incubation, the patient can infect those around him.
How long is the contagion period?
Since the beginning of the health crisis, scientific research has been carried out to determine the duration of the contagion of a person affected by Covid-19. At the CHU Saint-Pierre in Brussels (Belgium), medical teams classified the disease into three gradations. Doctors also calculated how long a patient was contagious:
Patients with covid at home: the average period of contagion is about 7 days after the appearance of the first symptoms.
Covid patients hospitalized, but not admitted to intensive care: the average period of contagion is 7 to 14 days after the declaration of the first symptoms.
Covid patients hospitalized and placed in intensive care: the average contagion period is 14 days or more after the onset of the first manifestations.
However, there are exceptions. "We see that those who infect the longest are those who maintain the symptoms for the longest time, but for the few people who have a fever longer (...) this rule of no contagion after 7 days does not apply", explained Charlotte Martin, infectious disease specialist.
An incubation period estimated at 11 days.
The National Center for Infectious Diseases of Singapore (NCID), with the support of a cohort of infectious disease specialists and the Academy of Medicine, also published a study on the duration of contagion of people who contract the virus.
Revealed on May 23, this investigation followed 73 patients affected by Sars-CoV-2 and hospitalized in Singapore. The patients underwent PCR (polymerase chain reaction) tests, the aim of which is to detect the presence of pathogens by removing cells from the back of the nose with a swab. Finding a small amount of the virus in the body does not necessarily mean that it is always viable or infectious, according to the study authors.
Eleven days after the first symptoms appeared in the subjects, the scientists were unable to isolate or grow the virus. According to them, patients would no longer be contagious even if screening tests remain positive. Therefore, the microorganism could no longer infect other people.
At the moment, these results have not yet been evaluated by the Ministry of Health, but they could have an impact on the future deconfinement strategies that the city-state will implement. In Singapore, the second wave of the virus was stronger than the first.
Covid-19: Are Patients Still Contagious After Recovery?
Last March, Chinese researchers analyzed the problem of contamination in patients cured from Covid-19. His work has been published in the scientific journal The Lancet. During the investigation, they observed 191 patients from two hospitals in Wuhan.
Results: the virus was still present in salivary secretions in a third of the subjects for 8 to 37 days. During the study, the scientists were still unsure whether these patients could still infect other people.