The Human Challenge Programme

The Human Challenge Programme, part of the government’s Vaccines Taskforce, is a partnership between the government, the NHS, academia and the private sector to establish human challenge studies for COVID-19 in the UK.

The programme is funded by Department of Business, Energy, and Industrial Strategy (BEIS) through the Vaccines Taskforce and will be delivered through a partnership between government, hVIVO, Imperial College London, and The Royal Free London NHS Foundation Trust.

This partnership will explore the use of human challenge studies to improve and accelerate the development of vaccines and treatments against COVID-19 and will create a UK-based infrastructure for future human challenge trials supporting the world’s biotech and pharmaceutical industries.

The first stage of this project will explore the feasibility of exposing healthy volunteers to COVID-19. In this initial phase, called the Virus Characterisation Study, the aim is to discover the smallest amount of virus it takes to cause a person to develop COVID-19. Imperial College London is the study sponsor, and the study will be conducted by hVIVO at the Royal Free Hospital in London, under the scrutiny of hVIVO’s highly trained scientists and medics. The study received ethics approval from a specially convened Research Ethics Committee in February 2021 and the study began in March 2021.

hVIVO is expanding its Clinical Operations in London to facilitate this work, learn more about openings at

hVIVO’s, state of the art facility at Queen Mary’s Bioenterprise Centre, London, is booked to maximum capacity until December 2021 and will continue to be used to deliver the Company’s traditional challenge study contracts, alongside the 19-bed Whitechapel Clinic that opened in January 2021.

Are these studies still needed with approved vaccines available?

  • First generation vaccines are not the final answer to eradicating the virus. Uneven vaccine delivery and breakthrough infections mean that outbreaks will continue to happen for months and years to come.
  • New variants of the virus mean vaccines will likely have to be adjusted to ensure effectiveness but our capacity to test them in field studies alone will be difficult. Human challenge will be the fastest way to compare old and new vaccines.
  • One of the benefits of a human challenge study is that it enables the rapid study of volunteers’ natural immune response to Covid-19 infection which helps doctors better understand how the virus affects people, how to detect symptoms early, and also how each vaccine works.
  • By testing vaccines side by side in a challenge study, it is possible to quickly identify which is the most effective.

The Human Challenge Programme will be able to help answer these questions.

Once the characterisation study is completed, this Human Challenge Study model can be utilised to conduct COVID-19 Human Challenge Studies from mid-2021 subject to regulatory approvals.

Individuals interested in taking part in this research can visit to learn more.

About Human Challenge Studies

In human challenge studies a small number of healthy volunteers in a controlled setting are exposed to an infectious agent, in this instance, COVID-19, and scientists and medics assess how effective vaccines or treatments are against the disease and identify any side effects.

Human Challenge Studies have been safely carried out for many years and played important roles in progress against diseases including malaria, typhoid, cholera, norovirus and flu. They are among the most efficient and scientifically powerful means for testing vaccines. hVIVO has safely completed 50 Human Challenge Studies since it was established in 1989 which included inoculating over 3,000 volunteers using viruses such as Influenza, Respiratory Syncytial Virus and Human Rhinovirus.

hVIVO FluCamp Challenge Studies


The safety of volunteers in any clinical study is always paramount; the partnership developing the human challenge model is working closely with the UK’s regulatory and ethics bodies to provide assurance that it is following established guidelines associated with clinical studies and that the design of the study minimises the risk of harm. The characterisation study received ethics approval from a specially convened Research Ethics Committee in February 2021 and the study began in March 2021.

Participants in the initial characterisation study are carefully selected to exclude anyone with a characteristic that has been shown to increase the severity of COVID-19 infection.

The study is taking place in a clinical facility that allows doctors to monitor volunteers 24 hours per day and have immediate receipt of medical care if required. Volunteers will be monitored for up to a year after receiving the virus, to ensure their long-term well-being.

The prevalence of COVID-19 rises and falls in populations, making it difficult for traditional vaccine trials to assess if vaccines work because those testing the vaccine may not be naturally exposed to it; as Human Challenge Studies deliberately infect the volunteers it is possible for scientists to establish efficacy very quickly.

As with any of our studies, we will be maintaining volunteers’ anonymity until the study has completed. At this time, in order to maintain the scientific integrity of the study, we are unable to disclose further details of any results gathered thus far. Individuals interested in taking part in this research can visit to learn more.