A COVID-19 vaccine trial in the UK has only a 50 percent chance at success, down from earlier estimates of 80 percent, the professor co-leading the development of the vaccine told a British newspaper.
A University of Oxford team led by Hill moved to human trials in April, making the experimental vaccine one of only a handful to reach that milestone.
“We said earlier in the year that there was an 80 percent chance of developing an effective vaccine by September,” he told The Telegraph.
“But at the moment, there’s a 50 percent chance that we get no result at all.”
Hill serves as director of Oxford’s Jenner Institute, which has teamed up with drugmaker AstraZeneca to develop the vaccine, of which the UK government has already promised to buy up to 100 million doses.
“The speed at which this new vaccine has advanced into late-stage clinical trials is testament to Oxford’s groundbreaking scientific research,” AstraZeneca executive Mene Pangalos said.
AstraZeneca Chief Executive Pascal Soriot said last month that he was hopeful the study could provide answers on vaccine efficacy as early as June or July.
Oxford University said that if community transmission drops, this process could take longer.
“If transmission remains high, we may get enough data in a couple of months to see if the vaccine works, but if transmission levels drop, this could take up to six months,” the university said in a statement.
AstraZeneca recently announced a $1.2 billion deal with the U.S. government to produce 400 million doses of the trial vaccine.
The dilemma of reduced community transmission has led some scientists and politicians to consider intentionally infecting people with the virus for the purpose of carrying out a meaningful vaccine trial.
The controversial method is called human challenge studies (HCS), and it involves healthy volunteers being injected with a candidate vaccine or a placebo followed by a weakened version of the virus.
Dr. Rajeev Fernando, infectious disease specialist and rapid responder at three New York hospitals, supports HCS if it can speed up the process of finding a vaccine.