Covid-19 Study Shows How Fast It Can Infect, And Where

It was detected first in the throat, much earlier than in the nose

British scientists have completed a world-beating challenge study on Covid. So, what is a challenge study?

It allows doctors to observe healthy people with Covid throughout the whole infection, something that's not possible with Covid patients.

In the study, 36 healthy young adults with no immunity to the coronavirus were monitored.

Participants aged 18-30 years, unvaccinated against Covid-19 and with no prior infection of the disease, were given a low dose of the virus introduced via drops up the nose and then carefully monitored in a controlled environment during a two-week period.

They were exposed to the lowest possible dose of virus to cause infection, roughly equivalent to the amount found in a single droplet of nasal fluid when someone was at their most infectious.