Covid-19 symptoms take time to go away – CNN

Covid-19 patients may need to wait more than a month before being tested again to see if they have cleared the virus, and one in five negative test results could be false, according to research published Tuesday in the British Medical Journal.

Dr. Francesco Venturelli, from the University of Modena and Reggio Emilia, and his colleagues studied 1,162 patients in the Italian province of Reggio Emilia who tested positive for COVID-19 using a polymerase chain reaction (PCR) test.

The patients were reexamined about 15 days after their first test, 14 days after the second, and nine days after the third. The researchers established these time intervals according to the Center’s recommendations. European for Disease Control and Prevention.

About 60.6% of the patients who recovered tested negative for COVID-19 on their first follow-up test. Another test confirmed that negative result in only 78.7% of these patients, which, according to the team, suggests that about one in five negative tests are false negatives. They say this could mean that many continue to shed the virus after testing negative and unknowingly pass it on to others.

The researchers determined that a patient had cleared the virus once he tested negative in two consecutive PCR tests. Overall, it took patients around 30 days from diagnosis and 36 days from symptom onset to clear the virus.

Older patients and those with more serious illnesses took a little longer to clear the virus. The time increased from 35 days for those under 50 to 38 days for those over 80. Outpatients took about 33 days, while hospitalized patients took about 38 days.

At 34 days after patients first noticed symptoms, almost 87% of them tested negative. This suggests that patients may need to wait a month or more to determine if they have actually cleared the virus, the researchers said.

The team notes that understanding the timing of viral shedding is key to determining testing strategies and ensuring that people don’t have to spend unnecessary time in isolation. They say that postponing follow-up testing of those who are no longer experiencing the disease or symptoms could increase the efficiency and performance of testing strategies.

The U.S. Centers for Disease Control and Prevention advises Americans that they do not need a second test for coronavirus. “Unless your illness requires hospitalization, you can return to your normal activities (for example, work or school) after 10 days from the onset of symptoms and 24 hours after the fever has subsided on its own (without the help of fever-reducing medications) ”, he advises.

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