A study found that some COVID-19 infected individuals released the virus for 12 days. The photo is unrelated to specific expressions in this article. [Image source=Pixabay]
[Asia Economy Reporter Hwang Sumi] A study has found that some COVID-19 infected individuals released the virus for up to 12 days.
On the 2nd (local time), CNN reported that Dr. Christopher Choo's team at Imperial College London (ICL) published the results of a deliberate COVID-19 infection experiment conducted last March on healthy volunteers aged 18 to 30 in the international medical journal Nature Medicine.
CNN also noted that the study was controversial because it involved deliberately infecting people with the virus or pathogen.
The research team selected healthy volunteers with no COVID-19 risk factors such as overweight or obesity, kidney or liver dysfunction, heart disease, or lung and blood problems. Additionally, the 10 initially infected participants were given the antiviral drug Remdesivir to reduce the possibility of severe progression.
Subsequently, the participants were inoculated with small droplets containing the COVID-19 virus into their nasal passages through a long, thin tube, and their infection status and symptoms were monitored 24 hours a day in negative pressure isolation rooms for two weeks.
As a result, about half of the participants, 18 people, were infected with COVID-19. Two were asymptomatic, and the 16 who showed symptoms all exhibited mild reactions such as nasal congestion, sneezing, and sore throat.
Furthermore, 83% of the confirmed cases lost their sense of smell. Although the severity varied, nine people could not smell anything at all. Most of the olfactory loss disappeared after six months.
The research team stated that the incubation period of COVID-19 is short, with virus shedding starting two days after infection and continuing for about six and a half days, but some infected individuals released the virus for up to 12 days.
According to the team, the virus was detected in the throat 40 hours after inoculation and in the nasal passages starting 58 hours after. A large amount of virus was shed even before symptoms appeared, and asymptomatic infected individuals also released large amounts of the virus.
Meanwhile, the U.S. Centers for Disease Control and Prevention (CDC) advises that individuals who test positive for COVID-19 can meet others after five days of self-isolation. Several countries, including the UK and the U.S., have shortened the isolation period for confirmed cases to five days, while South Korea still requires seven days.
According to research results so far, the Omicron variant has a shorter incubation period than previous variants. The average incubation period for the Delta variant was 4 to 5 days, but symptoms appeared within 2 to 3 days after infection with Omicron.
Dr. Vicente Soriano, an infectious disease expert at La Rioja International University in Spain, told the BBC that the virus can form within a day after exposure to Omicron. He also stated that assuming the Omicron variant remains in the body for seven days and no symptoms appear afterward, the virus is no longer contagious.
Dr. Soriano added, "Confirmed cases can test positive from the second day after infection and can transmit the virus to others for 3 to 5 days thereafter," but he cautioned, "This is medicine, not mathematics, so there should be some allowance."
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