Ethics
Review by an ethics committee is one of a series of safeguards intended to protect people taking part in all clinical research studies. It is a thorough process and there are many principles that are considered during the review, including weighing up the benefits against the risks. Another important consideration is making sure the potential participants receive high-quality, comprehensive information about the study in a timely fashion. The information about this controlled human infection study sent to and discussed with potential volunteers is very detailed and there are measures in place to make sure it is understood, so potential volunteers have a full picture of what the risks are and what the study entails before agreeing to take part (this is known as informed consent).
You can find out more about Research Ethics Committees (RECs) and the Health Research Authority (HRA) approvals on the A REC is made up of experts from different backgrounds (for example doctors, clinical trial experts, and scientists) and members of the public.
This study received ethical approval to commence on Tuesday 7th July 2026 by the Oxford A Research Ethics Committee.
Safety
No clinical study is completely risk-free, but the researchers who design and conduct controlled human infection studies have done everything possible to minimise the risks to the volunteers who take part, the study staff, and the wider community. The research teams also ensure that potential volunteers are fully informed about the risks before agreeing to take par during the process of informed consent.
SARS-CoV-2 is still causing disease ranging from asymptomatic (no symptoms) or mild illness to severe respiratory disease that can also affect other parts of the body in large numbers of people throughout the world. Humans have only experienced infections with this virus since late 2019 and the full range of symptoms or diseases caused by COVID-19 is still being investigated. Therefore, at present it is not possible to fully predict all potential risks to you from participating in this study, including long term risks.
Some people when infected with COVID-19 experience no symptoms at all. More severe cases of COVID-19 disease are usually seen in the elderly (over 65 years of age) and those with pre-existing medical conditions (such as diabetes). Although the risks of hospitalisation and death are thought to be very low in healthy adults, the factors that might increase the risk of such events are not completely known and therefore may not be detected in the screening process prior to entering the study.
The participants allowed to join the study are at the lowest risk of becoming severely unwell with COVID-19; they are vaccinated against COVID-19 and in good health, verified by a number of screening safety tests and assessments and a thorough review of their medical history. During the study, participants might get common symptoms of COVID-19 (including fever, tiredness, a cough, and changes to taste/smell), but these are expected to be mild and of short duration (1-2 weeks).
There is a small risk that participants could of the volunteers getting long COVID, with more prolonged symptoms that can last for months. Some of the common symptoms reported are loss of smell/taste, tiredness and brain fog. Participants will be monitored for 6 months after being exposed to the virus.
Severe disease or death due to COVID-19 in this population is very uncommon, but there is still a small risk. However, the risk to participants in the study becoming seriously unwell or dying is relatively lower, because they are screened for underlying health conditions and other factors that increase the chances of severe disease.
There are also other measures in place during the study to minimise these risks, including giving the volunteers the smallest amount of virus needed for infection and close monitoring for early signs of more serious symptoms.     
If any of the volunteers show any concerning symptoms, they will be moved from the quarantine unit where the study is taking place into the main hospital where the specialist critical care of infectious disease would take over their care.