Coronavirus patients highly infectious for first 9 days, according to new study

People who contract the new coronavirus are most likely to be highly infectious for nine days after the onset of symptoms, a new study has found, reinforcing the need for self-isolation for at least 10 days.

The peer-reviewed research, published in the Lancet medical journal on Thursday, analyzed hospitalized patients who had tested positive for the COVID-19 disease and found that the live virus, which causes infection, was not detected nine days after the symptoms started.

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“Our findings are in line with contact tracing studies which suggest the majority of viral transmission events occur very early, and especially within the first five days after symptom onset, indicating the importance of self-isolation immediately after symptoms start,” lead author Muge Cevik, of the University of St Andrews, said in a statement.

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“In patients with non-severe symptoms, their period of infectiousness could instead be counted as 10 days from symptom onset,” she added.

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Most countries, as per World Health Organization (WHO) guidelines, recommend 10 days of self-isolation for COVID-19 patients.

The Public Health Agency of Canada recommends at least 10 or up to 14 days of home isolation for symptomatic and asymptomatic cases.

The time between infection and the onset of symptoms can range from one to 14 days, which is why a two week-quarantine period is enforced in most countries after travelling or if you have come in contact with a confirmed case.

Most infected people show symptoms within five to six days.

Dr. Barry Pakes, a public health physician and professor at the University of Toronto, said this latest meta-analysis, which is looking at various studies, does not reveal new information, but helps understand our policy-making better.

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“Our guidance right now is that anyone who has been infected can come out of their safe self-isolation after 10 days, which is very much in line with the findings,” he told Global News.

“It (the study) does suggest that asymptomatic and symptomatic people don’t have significantly different viral loads and significantly different ability to infect. I think that’s probably as a result of this study being done on mostly hospitalized patients, so that’s not very helpful for making policy,” Pakes added.

“But everything that is in this study is more or less aligned with what we’re doing already, which is a good thing.”