While most people try to avoid getting infected, others get infected to help science! For the first time since the start of the pandemic, healthy people have been infected with the coronavirus as part of a scientific study conducted by scientists from University College London and Imperial College. The former is somewhat controversial, but allows a more accurate study of the course of infection, the appearance and duration of the most common symptoms, since the exact moment of contact with the virus is known, as well as the amount of virus during this infection. And this is while controlling for other environmental factors that can affect the course of the infection. The results were published on March 31, 2022 in the journal NatureMedicine. Here’s what they tell us about the coronavirus infection.
Lessons from the first controlled trial of coronavirus infection
In total, the study involved 34 healthy adults aged 18 to 29 years who were not previously infected with coronavirus and not vaccinated against this pathogen, which was approved by the ethics committee of the UK Medical Research Authority (HRA). Participants were infected with nasal drops containing the Sars-CoV-2 strain that was prevalent before the alpha variant emerged. After being vaccinated, they were observed in the hospital in separate rooms for at least 14 days and had to stay there as long as the virus was still detected in their bodies. An emergency protocol was introduced in case one of the participants developed severe Covid-19 using Regeneron monoclonal antibodies, but none of the participants required this treatment.
The virus is first found in the throat.
Approximately half of these people (18) developed an infection detectable by PCR. The virus was detected first in the throat (40 hours after contact), then in the nose (58 hours after contact). The viral load then increased very rapidly, peaking at 112 hours in the throat and 148 hours in the nose. But peak viral load was much higher in the nose. Thus, detection is faster in the throat, but more reliable in the nose due to the higher viral load.