World’s 1st trial where subjects were deliberately infected gives unique Covid insight

A groundbreaking study involving the world's first Covid-19 trial where 36 volunteers were deliberately infected with the virus has revealed a unique insight to scientists about the early stages of the disease, BBC reported.

As part of the trial, the volunteers -- aged 18-30, healthy and unvaccinated -- were given the virus at the Royal Free Hospital in London.

The outcomes revealed where and when the virus takes hold in the body. Some of the volunteers were also found to be able to resist infection, according to the BBC report.

Similar trials in future could help scientists study infections at the earliest, even before development of symptoms, and produce the next generation of Covid-19 vaccines and medicines.

"It's a really unique study," Prof Christopher Chiu, from the Institute of Infection, at Imperial College London, told BBC, adding, "Lateral flow tests correlate very well with the presence of infectious virus."

"Even though in the first day or two they may be less sensitive, if you use them correctly and repeatedly, and act on them if they read positive, this will have a major impact on interrupting viral spread."

Prof Sir Jonathan Van-Tam, deputy chief medical officer for England, said: "This important study has provided further key data on Covid-19 and how it spreads, which is invaluable in learning more about this novel virus, so we can fine-tune our response."

The Trial and Outcomes

An early Covid-19 variant was used from samples taken from a patient during the start of the pandemic.

Each volunteer was given an identical dose of Covid-19 virus of amount equal to a single droplet propelled out of a Covid-19 patient's nose during the peak of their infection.

Of the 36 volunteers, only 18 became infected.

Future research aims to focus on understanding how the others -- unvaccinated and without immunity from previous infections -- resisted the virus.

Among those infected, the first symptoms and positive test results appeared within just 42 hours.

Previously it was believed that a person would take around five days from virus exposure to exhibit the first symptoms.

The greatest concentration of virus was found in the nose after it took foothold in the throat, which yet again stressed the importance of using facemasks that cover both.

The infection peaked about five days after the exposure and could be detected up to 12 days later.

The volunteers had mild symptoms but some had a prolonged loss of their olfactory sense.

Recent variants will be explored in further similar trials.

The fact that it is safe to perform such voluntary trials has opened up new possibilities of research.

Similar trials in history yielded advances in medicine, for example the new Typhoid vaccine.

The findings of the trial have been published online but are yet to be formally reviewed by other scientists.