The Speaker
Monday, 20 May 2024 – 22:39

What are human challenge trials?

It has been reported that a facility in East London could host the world’s first COVID-19 human challenge trials from early next year to try and aid the race for a vaccine against the Coronavirus.

What though are human challenge trials, how do they work and are they ethical? Read on to find out more…


What exactly is a human challenge trial?

According to a guidance document from the World Health Organization, human challenges trials are trials in which “participants are intentionally challenged (whether or not they have been vaccinated) with an infectious disease organism”.

In the case of COVID-19 human challenge trials, it has been reported that healthy volunteers could be inoculated with a Coronavirus vaccine and then later deliberately infected with a “challenge” dose of Sars-Cov-2 (COVID-19).

The conducting of human challenge trials would usually take place in controlled conditions and the dose given to participants may be close to the wild-type of the virus or in some way potentially adapted or genetically modified.

Challenge trials have previously been used in developing vaccines and treatments for typhoid, malaria and other diseases.


Why would you deliberately give someone an infectious disease?

A human challenge trial may be used for different reasons, one being to answers questions about the efficiency of a potential vaccine. Vaccines usually take years to develop, but due to the massive adverse impacts of COVID-19 on the world, researchers and scientists have been accelerating the development of potential vaccines.

In theory, the use of human challenge trials could allow many potential vaccines to be tested in a short space of time, which supporters of the concept hope will increase the speed at which a safe and effective vaccine can be developed and approved for use.


What about the ethics of all this?

It may not come as a big surprise that human challenge trials are seen by many to be controversial. The Coronavirus pandemic has led to the deaths of over 41,000 people in the UK alone – the virus can be deadly, so deliberately giving it to people does raise some ethical questions.

Despite some concerns over their ethics, the trials have been gaining support in recent times, with COVID-19 impacting the way we all live.

Before a challenge trial could take place, it would have to be approved by the UK’s Medicines and Healthcare products Regulatory Agency and also an independent ethics committee. 

According to reports about challenge trials in the UK, the challenge would be given to healthy, young volunteers (who are less likely to become seriously ill) who would likely receive a compensation payment for taking part. Various safety measures would have to be in place before a trial could be approved, including a “rescue remedy” in case participants became seriously ill. Those taking part in the trial would have to stay in quarantine during the trial, it is understood.


Have people volunteered for a trial in the UK?

1Day Sooner, a US organization founded in April 2020, has been running campaigns advocating for COVID-19 infection trials and has enlisted over 37,200 volunteers in countries around the world.

Around 2,000 potential volunteers have signed up for challenge trial studies in the UK according to a report by the Financial Times and 1Day Sooner is set to soon launch a petition to the UK Parliament asking for public funding for a biocontainment facility where it is hoped that trials could take place. 

It has been reported that clinical development services business hVIVO could run human challenge trials in England, with Imperial College London as the project’s academic leader.

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