REACT-2: real-time assessment of community transmission – antibody waning
Published 27 October 2020
Applies to England
© Crown copyright 2020
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/statistics/react-2-real-time-assessment-of-community-transmission-antibody-waning/react-2-real-time-assessment-of-community-transmission-antibody-waning
Methodology
During 3 rounds of testing (consisting of different individuals in each round), a representative cross-section of adult volunteers tested themselves with finger prick antibody stick tests (lateral flow immunoassay) between 20 June and 28 September 2020. Tests from rounds 1, 2 and 3 were carried out approximately 12, 18 and 24 weeks after the peak number of cases in early April. The test results were read directly by participants and uploaded via an online survey.
Results
Prevalence of antibodies in the community in England declined from 6.0% (95% CI, 5.8, 6.1) in round 1, to 4.8% (95% CI, 4.7, 5.0) in round 2 and 4.4% (95% CI, 4.3, 4.5) in round 3 over the 3 months of the study. These figures have been adjusted to take the performance of the device and sample distribution into account and represents 17,576 positive results from 365,104 participants.
There was a decline in the proportion of those testing positive for antibodies observed in all regions. There was a gradual decline in prevalence overall, except for in healthcare workers where the prevalence did not change over time. On construction of epidemic curves from each of the 3 rounds, there was limited evidence of new cases after early May overall, but some apparently ongoing transmission in health and social care workers into May and June.
There was a decline in prevalence between rounds 1 and 3 in all age groups, with the smallest overall decline in the youngest age group aged 18 to 24 years (-14.9%, 95% CI 21.6, -8.1), and largest in those who were 75 years and older (-39.0%, 95% CI -50.8, -27.2).
Those who did not report a history of COVID-19 showed the largest proportionate decline in prevalence of antibodies, with a decrease in prevalence from rounds 1 to 3 of 64.0% (95% CI -75.6, -52.3), compared to 22.3% (95% CI -27.0, -17.7) in those with COVID-19 confirmed on PCR.
Conclusion
During the period 20 June to 28 September 2020, SARS-CoV-2 antibodies were measured in the community in three rounds in England at an overall adjusted prevalence ranging from 6.0% in round one to 4.4% in round 3.
The reduction of people testing positive suggests of antibody waning at the population level.
Background
Read the: