Washington, January 31st - 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 stages of infection, a study has found.
The study, recently published in the journal Frontiers in Medicine, included 38 Brazilian patients who were followed weekly between April and November 2020.
Researchers at the Pasteur-USP Scientific Platform, a partnership between France’s Pasteur Institute, the University of Sao Paulo (USP) and the Oswaldo Cruz Foundation (Fiocruz) in Brazil, followed the patients until they were negative by RT two or three times in a row were tested -qPCR.
They found that it took an average of one month for the diagnostic test to come back negative.
“Of the 38 cases we tracked, two men and one woman were atypical in that they had the virus continuously detected in their bodies for more than 70 days,”
; said Marielton dos Passos Cunha, first author of the study.
“Based on this result, we can say that about 8 percent of people infected with SARS-CoV-2 can potentially transmit the virus for more than two months without necessarily showing symptoms in the final stages of infection,” Passos Cunha said.
The researchers wanted to know if a period of 14 days was really long enough for the virus to go undetectable and concluded that it wasn’t.
“It can take a month for a patient to test negative, and in some cases enrolled 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 a warning about the risk of limiting quarantine for Covid patients to seven, 10 or even 14 days after they test positive, as originally mandated by protocols to combat the disease, the researchers said.
It also reinforces the importance of vaccinations, social distancing and wearing masks, they said.
The difference between women and men in terms of duration of viral activity was not significant, averaging 22 days and 33 days, respectively.
In 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.