Some people infected with SARS-CoV-2 may be able to transmit the virus for longer than the recommended quarantine period, without having to show any symptoms in the final stages of infection, a study suggests.
The research, published recently in the journal Frontiers in Medicine, involved 38 Brazilian patients followed weekly between April and November 2020.
Researchers affiliated with 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 patients until they tested negative. of two or three times in a row by RT -qPCR.
They found that it took a month on average for the diagnostic test to be negative.
“Of the 38 cases we monitored, two men and one woman were not typical in the sense that the virus was continuously detected in their organism 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 percent of people infected with SARS-CoV-2 can transmit the virus for more than two months, without necessarily showing any symptoms in the final stages of infection,”
; Said Passos Cunha.
The researchers wanted to know if a period of 14 days was actually long enough for the virus to stop being detected, concluding that it was not.
“It can take a month for a patient to be negative, and in some cases included in our study patients remained positive for 71 to 232 days,” said Paola Minoprio, one of the coordinators. of the Platform and chief investigator for 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 first prescribed by protocols to fight the disease, the researchers said.
It also reinforces the importance of vaccination, social distance, and wearing a mask, he said.
The difference between females and males in terms of duration of viral activity was not significant, with an average of 22 days and 33 days respectively.
As for the three atypical cases, the virus remained detectable for 71 days in the female and 81 days in one of the two males.
None of them had comorbidities and all had mild Covid symptoms, the researchers said.
The other atypical male continued to test positive for the coronavirus for 232 days, then he tested negative three times by RT-qPCR, they said.