Antigen survey shows high prevalence

Real-time Assessment of Community Transmission (REACT) Study

https://www.imperial.ac.uk/medicine/research-and-impact/groups/react-study/

Imperial College London

Commissioned by the Department of Health and Social Care,

Ipsos MORI

Antigen and antibody testing surveys

Repeated, non-overlapping, cross-sectional surveys, of random samples of the population

Self-administered throat and nose swabs and questionnaire data

Irrespective of symptoms

To estimate community-wide prevalence

Unbiased by testing availability or behaviour.

28 January – REACT-1 round 8 final report

England during January 2021

High average prevalence

Regional heterogeneity of trends

SARS-CoV-2 infection in the community

REACT-1 survey of prevalence in the community in England

Repeated cross-sectional samples of the population

Between 6th and 22nd January 2021

N = 167,642 results

Positive results = 2,282 were positive

Giving a weighted national prevalence of infection of 1.57%

(95% CI, 1.49%, 1.66%)

No strong evidence for either growth or decay averaged over the period 6th to 22nd January 2021

R number over this period was estimated at 0.98

(0.92, 1.04)

Why not more reduction in cases?

Higher average levels of mobility

More people allowed to physically attend their workplace

A larger number of children eligible to attend school

Higher intrinsic transmissibility of the new variant

Trend during 6th Jan to 22nd Jan

Prevalence remained high throughout, with suggestion of a decline

Regional heterogeneity

Decreasing prevalence in South West

Increasing prevalence in East Midlands

Prevalence during 6th Jan to 22nd Jan

Prevalence highest in London at 2.83%

Prevalence nationally highest in age 18 to 24 year, 2.44%

Those over 65 years, 0.93%

Correlations for higher prevalence

Large household size

Single person households, 1.24%

Households of seven or more people, 3.05%

Living in a deprived neighbourhood

Two most deprived quintiles, prevalence of 1.79%

Two highest quintiles, 1.22%

Black and Asian ethnicity

Black and Asian ethnicity, increased prevalence, 3.07%

White participants, 1.14%

Healthcare and care home workers

Healthcare and care home workers, 1.48%
Other workers, 1.35%

Other key workers

Context

Prevalence of infection in early to mid January 2021…

Highest since May 2020

High and rapidly increasing prevalence in the second wave

Partly, more transmissible strain

First observed in southern England in September 2020

Conclusion

Infection remain much higher than those seen during lockdown in May 2020

Shallower downward trajectory

Unless the prevalence of infection in the community can be lowered substantially

The extreme pressure on health services will continue over the coming weeks …

and possibly months,

until the vaccination programme protects sufficient numbers of at-risk individuals

Essential that we continue to observe public health measures,

Including social distancing, face covers, hand-washing and isolation of cases

If sustained lower prevalence is not achieved rapidly in England, pressure on healthcare services and numbers of COVID-19 deaths will remain unacceptably high.

Source