The British government is exploring the possibility of clinical trials in which volunteers are deliberately exposed to coronavirus to test the effectiveness of vaccine candidates, the UK Department for Business, Energy, and Industrial Strategy (BEIS) revealed Wednesday in a statement.
"We are working with partners to understand how we might collaborate on the potential development of a COVID-19 vaccine through human challenge studies," a government spokesperson said.
"These discussions are part of our work to research ways of treating, limiting and hopefully preventing the virus so we can end the pandemic sooner," the spokesperson added.
In so-called "challenge trials," researchers give study subjects an experimental vaccine and then intentionally expose them to coronavirus to see if the vaccine works. Such trials were used in early research with smallpox, yellow fever and malaria.
However, deliberately infecting study participants poses more risks and raises ethical concerns, compared to randomized controlled trials, where study subjects receive a vaccine or a placebo, and researchers monitor to see if they become ill as they go about their daily lives.
The World Health Organization issued guidance in May saying challenge studies can be "substantially faster" and more effective than other methods, in part because fewer participants need to be exposed to experimental vaccines and because they can be used to compare potential vaccines.
It also said controlled infection trials could be ethically acceptable if they met certain criteria. These include choosing young and healthy adults as participants, starting with low doses, ensuring public engagement, and providing high-quality care and close monitoring.
But in July, members of the US National Institutes of Health "Accelerating Covid-19 Therapeutic Interventions and Vaccines" (ACTIV) Working Group said such trials would not hasten development of a vaccine.
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