Frequently asked questions

What is REACT?

The REACT programme is a series of studies that are seeking to improve understanding of how the COVID-19 pandemic is progressing across England. To do this, the programme is carrying out two major pieces of work that are looking at the possibility of using home sampling and testing to track the infection.

The first, REACT1, will roll out antigen (swab) tests to 100,000 randomly selected people across England. This will examine how widely the virus has spread and how many people are currently infected with the coronavirus.

The second, REACT2, will assess a number of different antibody tests to see how accurate they are and how easily people can use them at home. Antibody tests are designed to tell individuals if they have had an immune response to the infection. These tests will offer an indication of how far the virus has spread across the country and what proportion of the population have been infected and recovered.

Why are you doing these studies?

As the Government plans strategies to ease lockdown, it is vital to understand how many people have been or are currently infected with the coronavirus. This will help guide policies on continued social distancing and other control measures.

Measuring the presence of coronavirus antibodies in the population could help us estimate how many people have been infected with the virus, while also improving our understanding of the immune response to the virus. But before any home antibody tests can be rolled out for widespread use, we need to understand how easy these tests are to perform at home, and how reliable they are. This study will help answer these questions and inform public health policy and government testing strategy.

What’s the difference between the antigen and antibody tests?

Antigens are anything that can cause an immune response in the body, like viruses and bacteria. In this case, the antigens that the REACT-1 test is looking for are bits of genetic material from the coronavirus. For the test, a person needs to take a swab of their nose and throat and send the sample off for testing in a laboratory. The lab test that detects whether coronavirus genetic material is present in a sample or not is called PCR (polymerase chain reaction). This indicates whether someone is currently infected.

Antibodies are immune molecules that the body produces in response to an infection. The tests that are being assessed in REACT-2 look for raised levels of antibodies to the coronavirus in an individual’s blood. The presence of antibodies could indicate that a person has previously been infected and has recovered from COVID-19, and could help to identify people who may be at lower risk of future infection. The test involves doing a finger prick, collecting a drop of blood onto a testing stick, and adding a few drops of a liquid that’s provided. You read off the result yourself shortly afterwards.

How accurate are the tests?

The antigen (PCR) test for coronavirus is generally considered the most accurate test to detect current infection with coronavirus.

Our REACT 2 study is shedding light on the accuracy of a number of different at-home finger-prick antibody tests and has also evaluated how easy they are to use in the home. Out of 11 different tests studied, the best could correctly identify individuals with coronavirus antibodies over 80% of the time, while also correctly ruling out those who don’t in more than 98% of tested individuals. These were found to be suitable for large-scale surveillance studies and one test has now been rolled out across England for this purpose, the results of which you can read about here

What if I get a positive result from my swab (antigen) test?

The results will be sent to the participant by post and, if positive, he or she will be asked to self-isolate along with other members of the household, in line with NHS and Public Health England advice. Those who receive a positive result will also be referred to NHS Test and Trace.

Results will be sent out approximately two weeks after they are sent-off by each participant.

What if I get a positive result from my finger-prick (antibody) test?

At the moment we don’t know how reliable these tests are and so the study is only looking at how easy the tests are to use, not the results of the test.

This means a positive test result does not necessarily mean you have had COVID-19 or that you are protected from getting it again, and a negative test result does not necessarily mean that you have not had COVID-19. Whatever your test result, it is important that you continue to follow the current Government advice that applies to you. This is why we are testing the accuracy of these kits and asking participants to not take any action or choose not to take an action based on the result.

Based on previous experience with other similar viruses, the presence of antibodies most likely does confer some level of protection, although we don’t know to what extent or for how long. We hope that this study will further our understanding of this.

When will the study be finished?

The results of REACT-1 and REACT-2 are being collected, analysed and published by Imperial College London as the research continues. 

You can read about our findings on this page

Why have I been asked to join this study?

The initial invitation was sent to your address after it was randomly selected. This random selection method ensures that the data we get accurately represents the whole country.

I’ve received a letter to join REACT but I can’t get the website to work, what do I do?

If you have been asked to take a swab test (REACT1) and you are able and willing to do so, please visit the website here, which will require you to enter your unique access code found on your invitation letter. If you are still stuck, please email our partners Ipsos MORI and their helpdesk will be able to assist. Please note this website is only for people who have been invited to participate.

If you have been asked to take a fingerprick antibody test (REACT2) and you are able and willing to do so, please visit the website here, which will require you to enter your unique access code found on your invitation letter. If you are still stuck, please email our partners Ipsos MORI and their helpdesk will be able to assist. Please note this website is only for people who have been invited to participate.

Who can I contact to get help about my involvement in this study?

We're working with our partners Ipsos MORI to conduct this study. If you have a question regarding taking part in the swab testing study, please contact them using these details:

  • 0800 157 7818

If you have a question regarding taking part in the antibody (finger-prick) testing study, please contact Ipsos MORI using these details:

  • 0800 819 9150

What will you do with my data?

This research is compliant with the General Data Protection Regulation (GDPR), a set of laws that protect your data and its privacy. All information that you give us will be treated in the strictest confidence and your identity will not be passed on to a third party other than the research team.

All of your personal data used and collected during this study will be stored by Ipsos MORI and Imperial College London in secure data centres and servers within the United Kingdom and European Economic Area.

We have taken a number of precautions to ensure that your data is safe and protected from loss, theft and misuse.

I want to participate in the research, can I sign up?

At the moment you can only take part if you have received an invitation letter. The research is being carried out with a random sample of people from across England to get a representative sample of the population, so we are not accepting volunteers. Please do not contact us at this stage if you are only looking to participate.

At a later stage, we will be recruiting more people to join REACT and may then look for volunteers. Once that stage has reached we will provide details of how to express interest in participating.

Is this a genuine study?

The REACT studies are legitimate research programmes being carried out in partnership by Imperial College London, the UK Department of Health and Social Care, and IpsosMORI. This study has received formal ethical approval from the South Central - Berkshire B Research Ethics Committee. You can find out more about the research in this news article.