Most people with mild COVID-19 are still contagious five days after symptoms start, a study suggests, challenging current NHS guidelines on how long to avoid contact with others.
Research by Imperial College London found that two-thirds of participants were still infectious at five days and a quarter were still infectious at seven days.
Current NHS guidelines are that people should try to stay home and avoid contact with others for five days.
There is no longer a legal obligation to self-isolate if you test positive for COVID-19[feminine].
The new study comes after another which found that most people infected with the Omicron variant didn’t even realize they had COVID-19.
The research is the first to unveil how long infectiousness lasts after natural COVID-19 infection in the community.
The study team performed detailed daily tests from the time 57 people were exposed to the virus to examine how much infectious virus they were shedding throughout their infection.
- The average duration of infectiousness was five days
- Only one in five participants were contagious before the onset of COVID-19 symptoms
- Two-thirds of cases were still contagious five days after their symptoms started
- A quarter were still infectious at seven days
- Lateral flow tests do not reliably detect the onset of infectiousness, but can be used to safely shorten self-isolation
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Study co-author Dr Seran Hakki of Imperial’s National Heart and Lung Institute said: “There is no longer a legal requirement to self-isolate if you test positive for COVID-19, but most people still want to self-isolate until they are infectious-free.
“Despite this, there is a lack of clarity on how to come out of self-isolation safely.
“Our study is the first to assess the duration of infectiousness, using real evidence of naturally acquired infection. Our results may thus inform advice on how to end self-isolation safely. “
She added: “If you test positive for COVID-19 or have symptoms after being in contact with someone with confirmed COVID-19, you should try to stay home and minimize contact with other people. “