S.ÃO PAULO, SP (FOLHAPRESS) – People infected with the new Sars-CoV-2 coronavirus developing Covid-19 transmit the virus more in the first five days after the symptoms begin.
After nine days of illness, no active viruses – which can trigger an infection – were found in samples, although the genetic material of the pathogen can be detected in these people weeks and even months after the onset of infection.
The results are from an article published on Thursday (19) in the scientific journal The Lancet Microbe by researchers from UK institutions.
The scientists reviewed data from 98 studies published between 2003 and June 2020 with information on viral load dynamics in patients with three coronavirus: Sars-CoV-2 (79 articles), which causes Covid-19, Sars-Cov (8) , which causes Sars (acute respiratory syndrome), and Mers-Cov (11), which causes Mers (Middle Eastern respiratory syndrome).
According to the researchers, data from these studies show that Covid-19 patients have the highest virus in their nose and throat (areas that scientists consider to be the main sources of transmission) just when symptoms appear, and the situation remains so. for about five days.
In the case of the other coronaviruses surveyed, the peak size of the virus in this region of the body usually appears in the second week of disease.
This would be one of the causes of the new coronavirus circulating in humans more easily than previous coronaviruses, as the patient with Covid-19 needs to make the isolation much quicker to prevent transmission of the disease. , the authors say.
Muge Cevik, a researcher at the University of St Andrews (Scotland) and lead author of the article, said in a press release that the results further suggest that a repeat PCR test (which detects the genetic material of the virus) may not be needed to discharge the isolation patient.
The test can remain positive for longer, and since it detects inactive parts of the virus, it does not necessarily indicate that the patient is infectious.
“In patients without severe symptoms, the infectious period can be ten days after the onset of the manifestations,” says Cevik. The guidelines for insulation vary from 10 to 15 days, depending on the organization. Generally, patients who are in a more serious condition are detained for longer.
“Understanding the transmission of the disease gives us tips on how to better achieve preventative measures,” says entomologist Maura Salaroli de Oliveira, from Sírio-Lebanese Hospital. “These results show that people should not underestimate Covid-19 signals, and that’s what we’ve seen.”
“As soon as symptoms such as pain, fever, loss of smell or taste begin, you should start isolating at home, without going into public places, until the test can be done. It is not appropriate to wait for the test result to justify then take the measure ”, Oliveira said.
According to the doctor, people should also be aware of the appearance of atypical manifestations of Covid, such as nausea and diarrhea.
In the article, the researchers say that there is not enough data to determine the possible transition period for so-called asymptomatic patients, a large cohort of people who were infected with Sars-Cov-2, but did not develop any of the symptoms of Covid-19.
Therefore, care such as social distance, wearing a mask and hand hygiene are essential to avoid infection, according to the entomologist. “I notice people on the street who distance themselves and wear a mask, but when they meet acquaintances they embrace and kiss, when anyone, even our friends, can be infected, ”Oliveira said. “We are all tired of these measures, but for now it must be so,” he said.