Recent research on 57 patients with mild COVID-19 was conducted to assess how long people are contagious and when they can safely be removed from isolation. The study that was published in The Lancet Respiratory Medicine is the first to show how long COVID-19 infection persists naturally in the population.

The research team carried out daily testing of the participants, from the time they were exposed to SARS-CoV-2, to determine how much contagious virus they were shedding throughout their infection. The results indicate that most symptomatic individuals are not infectious before symptom onset, but that two-thirds of cases are still infectious five days later. Additionally, they revealed that while lateral flow tests are less effective in detecting the onset of infectiousness, they do a better job of determining when a person is no longer contagious and may safely be released from isolation.

Participants completed daily questionnaires and collected daily throat and nasal swabs that were sent to PCR testing centres. After PCR testing, samples were examined to see if they contained an infectious virus and how contagious the virus was. In addition, the researchers performed 652 lateral flow tests on the samples to assess their effectiveness in diagnosing infectiousness as compared to PCR-positivity.

According to the study, the average number of days that persons were contagious was five. Currently, as per the NHS recommendations, people should stay at home and limit their social interactions to only five days. The study did not evaluate currently circulating Omicron variants. There is some proof that Omicron variants shed less frequently and have a lower viral burden than other variations.

Thus, based on their findings, the researchers advise those who have COVID-19 to isolate for five days after the onset of symptoms and then perform lateral flow tests starting on the sixth day. It is safe to come out of isolation if these return negative two days consecutively. (Hindustan Times, Aug 19, 2022)