One in ten people could have clinically significant amounts of potentially infectious SARS-CoV-2 beyond the 10-day quarantine period, warns new research.
The research, headed by the University of Exeter and supported by Animal Free Research UK, employed a newly developed test to see if the virus was still active. It was used on 176 samples from Exeter residents who had tested positive on routine PCR tests.
The study, which was published in the international Journal of Infectious Diseases, discovered that 13% of participants had clinically relevant amounts of virus after 10 days, indicating that they could still be infectious. Some individuals were able to maintain these levels for as long as 68 days.
To curb the spread of COVID-19, the scientists believe that this new test should be used in areas where people are vulnerable.
“While this is a relatively small study, our results suggest that potentially active virus may sometimes persist beyond a 10 day period, and could pose a potential risk of onward transmission,” Professor Lorna Harries, of the University of Exeter Medical School, oversaw the study said.
“Furthermore, there was nothing clinically remarkable about these people, which means we wouldn’t be able to predict who they are.”
The presence of viral fragments is tested in traditional PCR techniques. They can determine if someone has had the virus lately, but they can’t tell if it’s still alive and the individual is contagious. The test employed in the latest study, on the other hand, only returns a positive result when the virus is active and possibly transmittable.
“In some settings, such as people returning to care homes after illness, People continuing to be infectious after ten days could pose a serious public health risk,” added Lead author Merlin Davies.
“We may need to ensure people in those setting have a negative active virus test to ensure people are no longer infectious. We now want to conduct larger trials to investigate this further.”
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