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After almost 3 years, the UK Health Security Agency (UKHSA) are reviewing their approach to surveillance. We have paused data collection in the COVID-19 Infection Survey from mid-March 2023.

We would like to take this opportunity to thank all our participants - over half a million of them across all four nations of the UK - as well as several thousand study workers originally delivering home visits throughout multiple lockdowns. Their selfless contribution has made the COVID-19 Infection Survey an extraordinary achievement. The data collected will continue to be valuable for many years to learn more about how COVID-19 infection and vaccination affect future health outcomes.
See the press release here and comment from the Science Media Centre here.

**NEW ** COVID-19 and Respiratory Infections Survey **NEW ** 

The new COVID-19 and Respiratory Infections Survey (CRIS) aims to understand and manage COVID-19 and other respiratory infections. The data from the study are important in helping to understand:

  • the impact of COVID-19, long COVID and other respiratory infections on the lives of individuals, the community and on health services and how they are changing
  • potential pressures to help support the NHS and other services to prepare for future stressors, acting as an early warning system

A selection of COVID-19 Infection Survey participants will be invited by the Office for National Statistics (ONS) to join the study, which is separate from the COVID-19 Infection Survey - Oxford University is not involved in CRIS. More information is available here

COVID-19 Infection Survey (APRIL 2020 - March 2023)

The COVID-19 pandemic has had, and continues to have, a profound impact across the UK. This study aimed to find out how many people were still getting the infection and how many were likely to have had the infection, even if they hadn’t realised it at the time. This remained important as more people got vaccinated against COVID-19 with “boosters” and even more vaccinations after this, and more people got COVID-19. We needed to continue to monitor how many people were still getting COVID-19, with or without symptoms. We also needed to monitor how vaccinations, and having had COVID-19 before, affected our risk of getting COVID-19 in the future - and work out who might need vaccinating again in the future.

One way to find out whether a person has an infection is to directly look for the virus in their nose and throat. The main test used to diagnose COVID-19 uses a swab taken from someone’s nose and throat. Once an individual has recovered from the infection, the virus cannot be found any longer. One way the body fights infections like COVID-19 is by producing small particles in the blood called “antibodies”. It takes 2-3 weeks for the body to make enough of these antibodies to fight the infection. But once a person recovers, they still stay in the blood at low levels and give some protection against future infection. Getting vaccinated against COVID-19 is another way that people can get antibodies that can protect them against getting COVID-19. So scientists try to measure levels of both the virus and these antibodies to work out who has COVID-19 now (with or without symptoms) and who has had it in the past, or has developed antibodies against it after getting vaccinated.

In this study, which ran from April 2020 to March 2023, we wanted to find out how many people of different ages across the UK had COVID-19 over time, and how strongly their immune system reacted to COVID-19, particularly as more people got vaccinated and had COVID-19. We did this by testing for the virus in the nose and throat of people and by measuring levels of antibody in the blood. We also wanted to find out how many people had COVID-19 with symptoms or without knowing they had the infection because they didn’t have any symptoms. We wanted to do this in a group of people that reflected the population of the UK – so a range of ages and places where people live. We asked everyone aged 2 years or older in each randomly selected household to have a nose and throat swab, and for those aged 12 years and older to answer a few short questions (parents/carers will answer for younger children). Those aged 12 years and older took their own swabs using self-swabbing kits, and parents/carers used the same kits to take swabs from their children aged 2-11 years. For the first two years of the pandemic, this was been done at a home visit undertaken by a trained individual, but we then moved to a more flexible approach (described here). We asked adults aged 16 years or older from a randomly selected subset of these enrolled households to also give a sample of blood. At the start of the study, this was taken from a vein by a trained nurse, phlebotomist or healthcare assistant, but it was then taken by a fingerprick by the participant themselves. 

We asked people to take throat swabs repeatedly, every week for the first month (swab and questionnaire only, no blood draw), and then every month up to the end of the study (including monthly blood draws for those with blood taken originally). This was to find out how rates of infection and immunity changed over time in individual people, and whether they could get the virus again with or without having symptoms. We linked information people gave us from the survey visits to health data from the NHS (or equivalent bodies in the Devolved Administrations) and primary care whilst they were having study visits and for up to 15 years after they stop, to find out how much having COVID-19 and being vaccinated affected how often people had to go to hospital or visit their GP, and what health conditions they developed.

Overall, over 535,000 people from around 260,000 households across all four nations of the UK have taken part in the study.

  • From October 2020 to April 2022, up to ~150,000 individuals provided nose and throat swabs each fortnight in England, ~9,000 in Wales, ~5,000 in Northern Ireland and ~15,000 in Scotland (~179,000 total across the UK) (absolute numbers reflecting the relative size of the underlying populations). Up to ~125,000 people gave blood samples each month in England, and up to ~7,500, ~5,500 and ~12,000 per month in Wales, Northern Ireland and Scotland (~150,000 in total across the UK) to monitor how vaccination affects immunity at both the population and the individual level.
  • From April 2022 onwards, we invited existing participants to move from study worker home visits to posted sample kits and completing questionnaires online/by telephone. From April 2022, we aimed to test up to (maximum) 227,300 swab samples from individuals 2 years and older every 28 days in England, 15,650 in Wales, 10,050 in Northern Ireland and 23,200 in Scotland (maximum 276,200 total across the UK every 28 days, maximum 300,000 swab samples in total across the UK per month). We aimed to test up to (maximum) 90,850 blood samples taken from individuals 8 years and older every 28 days in England, 6,300 in Wales, 4,150 in Northern Ireland and 9,200 in Scotland (maximum 110,500 in total across the UK every 28 days, maximum 120,000 blood samples in total across the UK per month).

The information we got from the survey helped scientists and the government work out how to manage COVID-19 better, and helped to ensure that the NHS was not overwhelmed.

World-leading ONS Coronavirus (COVID-19) Infection Survey to continue with “digital” approach

The COVID-19 Infection Survey is changing. What does this mean for how the UK monitors the virus?   

If you are a participant and wish to complain about any aspect of the way in which you have been approached or treated, or how your information was handled during the course of the survey, please contact the dedicated study team on COVID-19@ONS.GOV.UK. Please do not contact the Nuffield Department of Medicine, as they will not be able to help you, and will not reply to general enquiries or questions about operational issues relating to the study.

You can find out more details of the study through its registration on ISRCTN21086382.