[04/02, 1:04 pm] 😍: The average duration between being exposed to the virus and its being discovered was 42 hours, according to the results of the world's first "human challenge" study, in which healthy young adults were purposely infected with Covid.
This is far smaller than the official government guidance estimate of a five to six-day "incubation period."
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According to a landmark trial in which healthy participants were purposely given a dosage of the virus, exposure to a single nasal droplet is enough to become infected with COVID-19.
The study, which was the first to track patients throughout the course of an infection, discovered that people often acquire symptoms rapidly – on average, within two days of coming into contact with the virus – and are most infectious five days later.
The research was done on a virus strain that existed before the Alpha, Delta, and Omicron versions appeared.
The findings, which were published on Springer Nature's pre-print service but have yet to be peer-reviewed, describe the outcomes of 36 healthy young people who had no immunity to the virus.
The volunteers were closely followed at the Royal Free Hospital in London's specialty section and showed no signs of illness.
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The study discovered that the infection begins in the throat and that the infectious virus peaks about five days after infection, at which point the viral load in the nose is considerably higher than in the throat.
The study also concluded that lateral flow tests are a reassuringly accurate indicator of the presence of infectious virus.
According to the findings, swabbing the nose and throat makes it easier to diagnose infections during the first few days.
Researchers infected volunteers with the coronavirus for a new study.
Scientists deliberately infected young, healthy volunteers with SARS-CoV-2, the coronavirus that causes COVID-19 — and now, they've shared their first results from that experiment.
The new study, published Tuesday (Feb. 1) in Springer Nature’s preprint database, In Review, has not yet been peer reviewed, but it could provide insight into how mild COVID-19 unfolds, from the moment of exposure to the point that the virus is eliminated from the body.
For the study, the researchers recruited 34 healthy volunteers ages 18 to 30; none of the participants had ever been infected with SARS-CoV-2 or received a COVID-19 vaccine, according to a statement. All participants tested negative for antibodies against SARS-CoV-2 at the start of the study, the researchers noted in their report.
The version of SARS-CoV-2 used in the study predated the alpha variant (or B.1.1.7, first detected in September 2020), but it differed from the original version of the virus in that it carried a mutation called D614G. This mutation affects the spike protein, which the virus uses to infect cells, and is thought to increase the virus's transmissibility.
After being exposed to the virus, 18 of the volunteers became infected, and of those, 16 developed mild to moderate symptoms, such as sore throat, headache, muscle and joint aches, fatigue and fever. Roughly a third (or 13) of the infected participants lost their sense of smell; for 10 of these people, their senses of smell returned to normal within three months, but the final three still experienced deficits at that point.
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