Some people with a mild COVID-19 infection could still potentially spread the disease for up to eight days after their symptoms disappear, a new study has suggested.
While the findings come from a very small study, it does highlight an extremely important point: even if you feel like you have recovered from COVID-19, there’s a chance you will still be infectious, so stay at home.
Reported in the American Journal of Respiratory and Critical Care Medicine, researchers from China took regular throat swabs from 16 patients with COVID-19, who were treated and released at a hospital in Beijing between January 28 and February 9, 2020. They found that the onset of symptoms (the incubation period) was five days among all but one patient and the average duration of symptoms was eight days. The average patient appeared to "shed" the virus for 2.5 days after symptoms disappeared, although this ranged between one to eight days.
Viral shedding suggests people could still be infectious, to some degree, from one to eight days after they start to feel better. Although it's unclear how contagious the patient might be during this recovery period, the risk is there.
"The most significant finding from our study is that half of the patients kept shedding the virus even after resolution of their symptoms. More severe infections may have even longer shedding times," co-lead author Dr Lokesh Sharma, from the Yale School of Medicine, said in a statement.
All of the patients had relatively mild symptoms, so it’s unclear whether the findings apply for people who develop more severe symptoms or have compromised immune systems. Nevertheless, it reiterates that people recovering from COVID-19 should remain in self-isolation long after symptoms clear up.
"COVID-19 patients can be infectious even after their symptomatic recovery, so treat the asymptomatic/recently recovered patients as carefully as symptomatic patients,” added the study authors in a joint message to the global medical community.
This is more or less in line with the current advice from some – but not all – national health authorities. The US Centers For Disease Control and Prevention (CDC) and the World Health Organization (WHO) both suggest people with symptoms of COVID-19 should quarantine themselves for 14 days after symptoms first develop.
In the UK, the National Health Service advises those with symptoms and living alone should remain at home for seven days after the first symptoms emerge. However, if you live with others and you’re the first in the household to have symptoms, then you must stay at home for seven days, while all other household members (whether they are ill or not)l must not leave the house for 14 days after the symptoms first emerged in the household.
Some might think two weeks is overkill, but that length of time is crucial to ensure the virus is no longer infecting anyone inside the house, whether the symptomatic or not. As this new research shows, a single person could remain infectious with COVID-19 even a week after their symptoms disappear.
So, even if you are feeling better, you could still be putting others at risk of the disease by leaving your house.