LONDON (Reuters), – The world’s first human challenge trial, in which participants were exposed to COVID-19 for research purposes, was a success. It involved healthy volunteers who then reported that the results of Wednesday’s study had been confirmed to be in safe hands.

This data is a strong support for the safety and reliability of the model. It could be used to help with future research that will test vaccines or medicines against COVID-19.

Open Orphan is running the project, launched in February last year, with Imperial College London, the British government’s vaccines task force and the clinical company  hVIVO.

Human challenge trials have been used by scientists for many decades as a way to discover more about diseases, such as flu and cholera.

Oxford University scientists conducted a second human challenge trial last April. The goal was to reinfect patients who were previously infected with COVID-19.

A total of 36 volunteers, aged between 18-29 and healthy men and women, were exposed in the Imperial trial to the SARS CoV-2 strain. The virus was closely observed and monitored within a quarantined environment. After being discharged from quarantine, they will continue to be monitored for twelve months.

According to the company, there have been no adverse effects and that the human-challenge study model has proven safe for healthy young adults.

“People of this age are thought to be the main drivers of the pandemic, and these studies which represent mild infection allow detailed investigation into the factors responsible.

Open Orphan, having established its model, stated it would be able conduct COVID-19 human test studies by 2022. This will require regulatory and individual approvals.

A pre-print server published the results from Imperial, but they are still being peer reviewed.

Imperial reported that symptoms begin to manifest about two days after the contact with virus.

The throat is the first place to get infected. Five days later, infectious virus levels peak and are significantly higher in the nose.

These tests also showed that the lateral flow tests were a reliable way to determine if an infected person has the virus and are therefore likely to pass it.

Imperial stated that 18 of the 19 volunteers were infected and 16 others developed mild-to-moderate symptoms similar to a cold, such as a runny nose or stuffy eyes, coughing up blood, and sore throats.

A few people experienced fever, fatigue, headaches and muscle/joint pains. None developed serious symptoms. Following the development of antibodies, 2 participants were unable to participate in final analysis.

Thirteen infected volunteers reported temporarily losing their sense of smell, but this returned to normal within 90 days in all but three participants – the remainder continue to show improvement after three months.

Participants did not experience any adverse effects or lungs changes.