March 29, 2024

UK to begin first challenge trials for Covid-19

Critics say that recent mutations make them useless

The first Covid-19 human challenge study has received ethical approval in the United Kingdom. Up to 90 healthy volunteers aged between 18 and 30 will be exposed to Covid-19 in a safe and controlled environment to increase understanding of how the virus affects people. It is due to begin in a few weeks.

The first-of-its-kind study for this virus will involve establishing the smallest amount of virus needed to cause infection, which will give doctors greater understanding of Covid-19 and help support the pandemic response by aiding vaccine and treatment development.

The safety of volunteers is paramount, says the government, which means this virus characterisation study will initially use the version of the virus that has been circulating in the UK since March 2020 and has been shown to be of low risk in young healthy adults.

Medics and scientists will closely monitor the effect of the virus on volunteers and will be on hand to look after them 24 hours a day.

Clive Dix, of the Vaccines Taskforce, said: “We have secured a number of safe and effective vaccines for the UK, but it is essential that we continue to develop new vaccines and treatments for Covid-19. We expect these studies to offer unique insights into how the virus works and help us understand which promising vaccines offer the best chance of preventing the infection.”

Human challenge trials are used to develop vaccines and treatments across multiple diseases including malaria, typhoid, norovirus, common cold and Influenza. Volunteers will be compensated for their time, to the tune of around £4,500 over the course of a year, which will include follow-up tests.

Human challenge trials for Covid-19 have been discussed from the time that the virus emerged and they have always been controversial. For a negative view, here are some comments from William Haseltine, a columnist for Forbes who used to be a professor at Harvard Medical School:

The risk to the 90 healthy volunteers who will be recruited for this trial is very real. The press release announcing the challenge claims that “the safety of volunteers is paramount” and highlights how only healthy young adults will be chosen. Yet it ignores the mounting evidence that even a mild case of Covid in a healthy young adult can lead to long term lung damage and other potentially serious lifelong symptoms. To make it worthwhile to put 90 healthy young people at risk for lifelong illness, the benefits have to be very real. But the reality is that this trial is likely to prove relatively meaningless.

Since the issue of human challenge trials for Covid-19 was first introduced last year, our understanding of the virus has evolved dramatically. We now know that the virus can change, and it can change quickly. One of the primary purposes of this vaccine challenge, at least according to the release, is to establish “the smallest amount of virus needed to cause infection, which will give doctors greater understanding of Covid-19 and help support the pandemic response by aiding vaccine and treatment development.” Yet given what we know of SARS-CoV-2 today, it is highly likely that the virus used in the challenge expected to begin in just a few weeks will be markedly different than the virus that the world will be dealing with when the results are released.

Michael Cook is editor of BioEdge

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