Imperial College London, in collaboration with Imperial College Healthcare NHS Trust and Chelsea and Westminster Hospital NHS Trust, and funded by the Wellcome Trust, are conducting a new human infection study (also known as a human challenge study) with SARS-CoV-2, the coronavirus that causes COVID-19.

This new study will follow on from the first COVID-19 human infection study carried out by researchers from Imperial, Royal Free London NHS Foundation Trust and the clinical company hVIVO last year. Findings from the first study have now been peer-reviewed and published in Nature Medicine and detail the outcomes in 36 healthy, young participants with no immunity to the virus. Read the full news story on the Imperial College news site to learn more.

In this new study, young, healthy volunteers will be deliberately infected with the delta-strain of the COVID-19 virus so that researchers can learn more about the infection and test new vaccines and treatments in the future.

This study aims to recruit up to 120 volunteers who will be given the virus by drops in the nose in a safe and controlled environment. Only volunteers at the lowest risk of becoming severely unwell (young adults between 18-30 years old, who have been vaccinated against COVID-19 and have no underlying health conditions) will be eligible to take part.

The study is taking place in a controlled quarantine unit at the Chelsea and Westminster Hospital in London, so the virus cannot be passed on to people outside the study. There are medical staff on hand all the time closely monitoring the volunteers.

To begin with, researchers at the Imperial Clinical Research Facility will conduct an initial screening assessment to determine eligibility for the study. If eligible, volunteers will then be invited to the quarantine unit at the Chelsea and Westminster Hospital. They will be given a dose of coronavirus and then monitored for a minimum of 14 days at the quarantine unit. Once the discharge criteria have been met, they will then leave the quarantine facility and continue in the study up to a year post inoculation and return to the Imperial Clinical Research Facility for five follow up visits.

If you are interested in finding out more, please read the full study information sheet: COVHIC002_PIS_V5.0_17.10.2023

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Why are we doing this research?

The purpose of this research is to look at the effects of infecting healthy participants with SARS-CoV-2 (COVID-19 or the “study virus”) – including immune responses in the blood and lining of their noses, before, during and after viral infection (administering the virus). This is called a COVID-19 human challenge model.

The information obtained from this study will allow us to better understand the human biological response to the COVID-19 infection (for example, to see if an initial episode of mild COVID-19 illness stimulates immunity (protection) against a future challenge (infection) and to learn why some people get sick and others do not/why some people have more and/or worse symptoms than other) as well as to test new vaccines developed to prevent COVID-19.

Who will participate in this study?

Up to 120 healthy volunteers who are:

  • aged between 18 to 30 years of age
  • vaccinated against COVID-19
  • healthy with no underlying medical conditions
What will the study involve?

The study will consist of three phases; a Screening phase, a Quarantine phase and a Follow-up phase.

Screening phase

Screening will take place at the Imperial Clinical Research Facility. Participants will have the opportunity to discuss the study with the research team and have their questions answered before signing a consent form. The study team will then collect data and samples from them to see if they would meet the eligibility criteria for the study. 

Quarantine phase

If the screening phase suggests that they are suitable for the study, we may then invite them to the quarantine unit at the Chelsea and Westminster Hospital where they will be given the study virus and requested to stay in their allocated quarantine room for 13-17 days for observation and to prevent the spread of infection.

Follow-up phase

After discharge from quarantine, they will have a follow-up phone call at Day 21 from the study team to check on their well-being and they will be requested to attend a scheduled clinic visit on Days 28, 90, 180, 270 and 360 back at the Imperial Clinical Research Facility.

What is the duration of this study?

Each participant will be in the study for approximately 12 months from screening to their last scheduled visit. 

Are there any potential benefits?

Taking part in the study is unlikely to provide health benefits but participants might develop some immunity to the study virus and benefit from a general health check at screening. They will be paid for their time if they take part (up to £4,500).

What should I do if I want to take part?

If you decide you want to take part, you should read the full Participant Information Sheet (COVHIC002_PIS_V5.0_17.10.2023) and then register your interest by completing the pre-screening questionnaire.

Recruiting now


We are looking for healthy volunteers aged 18-30 years old to take part in a new COVID-19 Human Challenge Study.

The study involves a screening visit, a quarantine stay, during which you will be deliberately infected with the COVID-19 virus and carefully monitored until discharge, followed by five follow-up visits over the course of 12 months.

If you are eligible to take part, you will be paid up to £4,470 for time and inconvenience.

If you are interested in finding out more, please read the full study information sheet (COVHIC002 Participant Information Sheet (.pdf)) and register your interest by completing our pre-screening questionnaire.

Contact us


To get in touch with a member of the study team, please email challenge-trial@imperial.ac.uk