Washington, January 31 - Some people infected with SARS-CoV-2 may be able to transmit the virus for longer than the recommended quarantine period, without necessarily showing symptoms in the final stage of infection, a study suggests.
The research, published recently in the journal Frontiers in Medicine, involved 38 Brazilian patients who were followed on a weekly basis between April and November 2020.
Researchers affiliated with the Pasteur-USP Scientific Platform, a partnership between the Institut Pasteur de France, the University of Sao Paulo (USP) and the Oswaldo Cruz Foundation (Fiocruz) in Brazil, followed the patients until ‘they test negative two or three times in a row by RT-qPCR.
They found that it took an average of a month for the diagnostic test to become negative.
“Of the 38 cases we followed, two men and one woman were atypical in the sense that the virus was continuously detected in their body for more than 70 days,” said Marielton dos Passos Cunha, first author of the research. .
“Based on this result, we can say that approximately 8% of people infected with SARS-CoV-2 may be able to transmit the virus for more than two months, without necessarily showing symptoms in the end stage of the disease. infection,” says Passos Cunha.
The researchers wanted to know if 14 days was really long enough for the virus to stop being detectable, concluding that it was not.
“It can take a month for a patient to test negative, and in some cases included in our study, patients remained positive for 71 to 232 days,” said Paola Minoprio, one of the Platform’s coordinators and principal investigator of the study.
The finding serves as an alert about the risk of limiting quarantine for Covid patients to seven, ten or even 14 days after they test positive, as originally prescribed by disease control protocols, the researchers said.
It also reinforces the importance of vaccinations, social distancing and mask-wearing, they said.
The difference between women and men in the duration of viral activity was not significant, averaging 22 days and 33 days respectively.
As for the three atypical cases, the virus remained detectable for 71 days in the woman and 81 days in one of the two men.
None of them had comorbidities and all had mild symptoms of Covid, the researchers said.
The other atypical man continued to test positive for coronavirus for 232 days, after which he tested negative three times by RT-qPCR, they said.