Pharmaceutical services company Open Orphan is running the project, launched a year ago, with Imperial College London, the UK government's vaccines task force and the clinical company, hVIVO.
The trial could lay the groundwork for future studies to test new vaccines and medicines against COVID-19.
Scientists have used human challenge trials for decades to learn more about diseases such as malaria, flu, typhoid and cholera, and to develop treatments and vaccines against them.
The Imperial trial exposed 36 healthy male and female volunteers aged 18-29 years to the original SARS-CoV-2 strain of the virus and closely monitored them in a controlled quarantined setting. They will be followed up for 12 months after discharge from the quarantine facility.
No serious adverse events occurred, and the human challenge study model was shown to be safe and well tolerated in healthy young adults, the company said.
"People in this age group are believed to be major drivers of the pandemic and these studies, which are representative of mild infection, allow detailed investigation of the factors responsible for infection and pandemic spread," said Chris Chiu, chief investigator on the trial and professor of infectious diseases at Imperial.
With the model established, Open Orphan said it should be able to contract or conduct COVID-19 human challenge studies in 2022, subject to individual ethics and regulatory approvals.
Eighteen of the volunteers became infected, 16 of whom went on to develop mild-to-moderate cold-like symptoms, including a stuffy or runny nose, sneezing, and a sore throat, Imperial said.
Some experienced headaches, muscle/joint aches, tiredness and fever. None developed serious symptoms. Two participants were excluded from the final analysis after developing antibodies between initial screening and inoculation.
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.British researchers have deliberately 'challenged' healthy volunteers with COVID-19, to be able to test future vaccines and therapies.
In April last year, Oxford University scientists launched another human challenge trial which sought to reinfect people who had previously had COVID-19 in an effort to deepen understanding about immunity, rather than infecting people for the first time.
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