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expert reaction to media reports that COVID-19 human challenge trials will take place in the UK in January

It has been reported that in January a COVID-19 challenge trial will start, in which participants are purposefully infected with COVID-19 in a controlled manner in order to test the efficacy of potential vaccinations. 


Dr Claire Waddington, Clinical Lecturer in Infectious Diseases, University of Cambridge, said:

“Controlled human infection models (“challenge models”) are well established as a way to accelerate the development of vaccines for a wide range of infections.  They are particularly useful when studying infections for which there is no reliable animal model, or where we have only limited data on the immunobiology of a disease.  For example, a controlled human infection model for typhoid fever has been used over the past decade to support the development of typhoid vaccines that are now being rolled out in high incidence countries and are likely to save thousands of lives.  Controlled human infection models have the advantage of allowing us to know exactly when people are exposed to the pathogen of interest so the response to infection and the protection of any vaccine used in the model can be directly and accurately investigated.  Safety is always of paramount importance in these studies, as it is in any study involving people.  As we gain more understanding of COVID-19, we are increasingly in a position to identify those people for who COVID-19 infection is a mild illness, and these people could safely participate in a controlled human infection study after a thorough medical assessment and consent process.  Such a model could give us some extremely useful information on how the immune system responds to COVID and what responses are protective, as well as providing a model for early testing of candidate vaccines.”


All our previous output on this subject can be seen at this weblink:


Declared interests

Dr Claire Waddington: “I don’t have any DoI other than having set up several challenge models previously, and wanting to set up a COVID model.”

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