REACT-1 round 9 interim report: downward trend of SARS-CoV-2 in England in February 2021 but still at high prevalence

  1. Steven Riley
  2. Caroline E. Walters
  3. Haowei Wang
  4. Oliver Eales
  5. David Haw
  6. Kylie E. C. Ainslie
  7. Christina Atchison
  8. Claudio Fronterre
  9. Peter J. Diggle
  10. Deborah Ashby
  11. Christl A. Donnelly
  12. Graham Cooke
  13. Wendy Barclay
  14. Helen Ward
  15. Ara Darzi
  16. Paul Elliott

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Abstract

Background and Methods

England entered its third national lockdown of the COVID-19 pandemic on 6th January 2021 with the aim of reducing the daily number of deaths and pressure on healthcare services. The real-time assessment of community transmission study (REACT-1) obtains throat and nose swabs from randomly selected people in England in order to describe patterns of SARS-CoV-2 prevalence. Here, we report data from round 9a of REACT-1 for swabs collected between 4th and 13th February 2021.

Results

Out of 85,473 tested-swabs, 378 were positive. Overall weighted prevalence of infection in the community in England was 0.51%, a fall of more than two thirds since our last report (round 8) in January 2021 when 1.57% of people tested positive. We estimate a halving time of 14.6 days and a reproduction number R of 0.72, based on the difference in prevalence between the end of round 8 and the beginning of round 9. Although prevalence fell in all nine regions of England over the same period, there was greater uncertainty in the trend for North West, North East, and Yorkshire and The Humber. Prevalence fell substantially across all age groups with highest prevalence among 18- to 24-year olds at 0.89% (0.47%, 1.67%) and those aged 5 to12 years at 0.86% (0.60%, 1.24%). Large household size, living in a deprived neighbourhood, and Asian ethnicity were all associated with increased prevalence. Healthcare and care home workers were more likely to test positive compared to other workers.

Conclusions

There is a strong decline in prevalence of SARS-CoV-2 in England among the general population five to six weeks into lockdown, but prevalence remains high: at levels similar to those observed in late September 2020. Also, the number of COVID-19 cases in hospitals is higher than at the peak of the first wave in April 2020. The effects of easing of social distancing when we transition out of lockdown need to be closely monitored to avoid a resurgence in infections and renewed pressure on health services.

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  1. ScreenIT

    SciScore for 10.1101/2021.02.18.21251973: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: Research ethics approval was obtained from the South Central-Berkshire B Research Ethics Committee (IRAS ID: 283787).
    RandomizationSince the first round of data collection in May 2020, in each subsequent round in each subsequent round between 150,000 and 175,000 randomly selected individuals ages 5 years and above, in England, have provided a self-administered throat and nose swab for RT-PCR testing for SARS-CoV-2.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: Thank you for sharing your code and data.

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Our study has a number of limitations. Because participation rates in our study may vary by a range of socio-demographic factors, it is possible that our sample is not fully representative of the base population, despite correcting for the sampling in our weighting procedure. However, unlike estimates based on symptomatic testing, we provide prevalence estimates among both symptomatic and non-symptomatic individuals from random samples of the population. Our study is therefore not subject to the biases driven by self-reporting, and health service capacity and performance present in similar data based only on tests of symptomatic individuals. We ask individuals to provide a self-administered throat and nose swab (parent/guardian for children ages 5 to 12 years) which may be less reliable than a swab administered by a health professional. However, we provide detailed instructions including video instructions, and have utilised the same approach across all rounds of REACT-1, so that within-study comparisons and trends in prevalence over time should be robust. In addition, we have established a cold chain from home to laboratory to preserve integrity of the samples, and use a single lab (with well-defined quality control procedures) to exclude between-laboratory variation. In conclusion, we have documented marked falls in prevalence in England during lockdown from January to February 2021. However, it should be noted that prevalence still remains high (prevalence now at a level l...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  2. Version published to 10.1101/2021.02.18.21251973 on medRxiv