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Covid-19 Vaccine Challenge Trial Underway

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(Ewa Urban, Pixabay)

20 Oct. 2020. Researchers in the U.K. are beginning a human challenge trial that intentionally exposes volunteers to SARS-CoV-2 viruses to test candidate vaccines. The challenge trial is a project of Imperial College London and the company hVIVO, a subsidiary of contract research organization Open Orphan, also in London, sponsored by the U.K. government’s Department for Business, Energy and Industrial Strategy.

The researchers say a challenge trial is a faster and more efficient way of testing vaccines than conventional clinical trials. In the current late-stage trials of Covid-19 vaccine candidates, thousands of volunteers are enrolled to ensure that a sufficient number of participants are eventually exposed to SARS-CoV-2 viruses to test the vaccine’s efficacy. These large numbers are required to reliably compute statistical probabilities of success. Human challenge trials, on the other hand, are designed to expose participants to the virus, thus needing much smaller numbers of participants, and providing results faster.

The team led by Imperial College’s infectious disease researcher Christopher Chiu, plans to begin the project, called the Human Challenge Programme, with a feasibility test of exposing volunteers to SARS-CoV-2 viruses. The researchers are recruiting volunteers age 18 to 30 to find the smallest amount of virus needed to cause an infection. Volunteers must have no underlying health conditions, nor any previous history or symptoms of Covid-19. The aim is to find the lowest dose possible to cause the virus to replicate in the body, but keep symptoms to a minimum. Once the minimal virus level is set, more volunteers will be enrolled to test various Covid-19 vaccine candidates.

“Our number one priority is the safety of the volunteers,” says Chiu in an Imperial College statement. “No study is completely risk free, but the Human Challenge Programme partners will be working hard to ensure we make the risks as low as we possibly can.” Chiu also notes that he and his researchers have “been safely running human challenge studies with other respiratory viruses for over 10 years.”

An ethics committee convened by the government’s Medicines and Healthcare products Regulatory Agency, or MHRA is overseeing the study. This group will first review and approve the study protocols before the researchers can begin recruiting participants.

The Open Orphan subsidiary hVIVO will conduct the challenge trial. The company signed a contract with the U.K. government to conduct the feasibility study, also known as a characterization study, to start immediately. hVIVO, which specializes in challenge trials, plans to carry out the study at the Royal Free Hospital in London, with a target date of May 2021. The characterization study is expected to bring hVIVO up to £10 million ($US 13 million). The company has also reserved three slots for assessing vaccines after the initial feasibility study, with the vaccine tests earning the company as much as £2.5 million for each vaccine.

The researchers and hVIVO are recruiting volunteers for the challenge trials at

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