Background The third wave of COVID-19 in England peaked in January 2022 resulting from
the rapid transmission of the Omicron variant. However, rates of hospitalisations and deaths
were substantially lower than in the first and second waves
Methods In the REal-time Assessment of Community Transmission-1 (REACT-1) study we
obtained data from a random sample of 94,950 participants with valid throat and nose swab
results by RT-PCR during round 18 (8 February to 1 March 2022).
Findings We estimated a weighted mean SARS-CoV-2 prevalence of 2.88% (95% credible
interval [CrI] 2.76–3.00), with a within-round reproduction number (R) overall of 0.94 (0·91–
0.96). While within-round weighted prevalence fell among children (aged 5 to 17 years) and
adults aged 18 to 54 years, we observed a level or increasing weighted prevalence among
those aged 55 years and older with an R of 1.04 (1.00–1.09). Among 1,195 positive samples
with sublineages determined, only one (0.1% [0.0–0.5]) corresponded to AY.39 Delta
sublineage and the remainder were Omicron: N=390, 32.7% (30.0–35.4) were BA.1; N=473,
39.6% (36.8–42.5) were BA.1.1; and N=331, 27.7% (25.2–30.4) were BA.2. We estimated an
R additive advantage for BA.2 (vs BA.1 or BA.1.1) of 0.40 (0.36–0.43). The highest proportion
of BA.2 among positives was found in London.
Interpretation In February 2022, infection prevalence in England remained high with level
or increasing rates of infection in older people and an uptick in hospitalisations. Ongoing
surveillance of both survey and hospitalisations data is required.
Funding Department of Health and Social Care, England.