The UK is to begin the world's first COVID-19 human trials to study the impact of the deadly virus on a healthy body's immune system, after receiving the approval of the country's clinical trials ethics body on 17 February.

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The initial study is intended to help scientists understand how the immune system reacts to the virus that causes COVID-19, and identify factors that influence how it is transmitted -- including how a person who is infected sheds infectious virus particles into the environment. The study will involve up to 90 carefully selected healthy adult volunteers being exposed to the virus in a safe and controlled environment. Our eventual aim is to quickly test which vaccines and treatments work best in beating this disease, said Chief Investigator Dr Chris Chiu, from the Department of Infectious Diseases at Imperial College London.

We are asking for volunteers aged between 18 and 30 to join this research endeavour to help us to understand how the virus infects people and how it passes so successfully between us, he said. The human challenge study, to begin in the next few weeks, is backed by a 33.6 million pound UK government investment and will be delivered by a partnership between Imperial College London, the Royal Free London NHS Foundation Trust and the clinical company hVIVO. Once the initial study has taken place, vaccine candidates, which have proven to be safe in clinical trials, could be given to small numbers of volunteers who are then exposed to COVID-19, helping to identify the most effective vaccines and accelerate their development.

Researchers and scientists around the world have made great progress in understanding COVID-19 and developing critical vaccines to protect people, but we are only part way up the mountain we need to climb, said UK Business Secretary Kwasi Kwarteng. While there has been very positive progress in vaccine development, we want to find the best and most effective vaccines for use over the longer term. These human challenge studies the world's first will take place here in the UK and will help accelerate scientists' knowledge of how coronavirus affects people and could eventually further the rapid development of vaccines, he said.

Similar human challenge studies have been used in the development of treatments for a number of diseases such as malaria, typhoid, cholera and flu. The new study will aim to establish the least amount of virus needed to cause COVID-19 infection. As there is much less information available about new virus variants, the doctors will use the original virus that has been circulating in the UK since March 2020. Researchers said the study will only involve volunteers who are young and healthy as we know that this group of people are at very low risk of becoming severely ill from coronavirus infection. The studies will take place in a specialised unit with very close monitoring and with medics on hand with treatments if they are needed.

The study has been reviewed by the UK Health Research Authority to ensure that it meets the highest ethical standards. The researchers stressed that the safety of the volunteers is of utmost importance and their health will be closely monitored throughout their time in the purpose-built quarantine unit. Volunteers will also be followed up for a year after their participation. 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, said Clive Dix, the Chair of the Vaccines Taskforce.

No one vaccine is likely to be suited to everyone so we must continue to develop new vaccines and treatments for COVID-19 coronavirus. This will help us to ensure that people across the UK and the world can be protected against this disease, he said. The virus being used in the characterisation study has been produced by a team at Great Ormond Street Hospital for Children NHS Foundation Trust, with support from virologists from Imperial. The Royal Free Hospital's specialist and secure clinical research facilities in London are specifically designed to contain the virus. Highly trained medics and scientists will be on hand to carefully examine how the virus behaves in the body and to ensure the safety of volunteers. Dr Andrew Catchpole, Chief Scientific Officer at hVIVO, added: We will start to see useful results very quickly after the commencement of the study. From the moment we inoculate someone with this virus, we will learn important information about disease progression and treatment. This crucial data feeds directly back into how to develop effective vaccines and better treatments because they identify what type of immune response needs to be triggered.