The latest preliminary surveillance data from the REACT-1 study suggest that, as of 1 March 2022, around one in 16 people were testing positive for COVID-19


COVID-19 infections in England have risen to a record high, new preliminary surveillance data have shown.

Based on swab samples taken from 109,459 people aged 5 years and older conducted between 8 and 31 March 2022, around one in 16 people were testing positive for COVID-19, or 6.37% of those sampled.

Scientists at Imperial College London (ICL) said that these results from the latest round of the REal-time Assessment of Community Transmission-1 (REACT-1) study suggest that the prevalence of COVID-19 as of 1 March was more than double that of the study’s previous findings, when one in 35 tested positive, or 2.88% of those sampled.

The study found that infections had risen in all age groups, and remained highest among primary school children, with 8.81% of 5–11 year olds testing positive.

Concern over future hospitalisation numbers

However, although the most recent trends suggest that the rate of new infections could be slowing in those aged between 5 and 54 years, infections may still be rising among older people, which ‘may increase hospitalisations and deaths, despite high levels of vaccination’, the study concluded.

The data from round 19, published as a preprint, suggest that COVID-19 prevalence at the end of last month was at its highest since the study began in May 2020, and was 40% higher than the first peak of the Omicron variant in January this year.

The BA.1 subvariant of Omicron has been almost completely replaced by the more transmissible BA.2 variant, scientists said. Compared with BA.1, the BA.2 Omicron sub-lineage appeared to have a growth rate advantage of 0.11. Viral genome sequencing showed that the proportion of lineages from those tested were 99.97% Omicron, of which 10.2% were of the BA.1, 89.7% of the BA.2, and 0.03% of the BA.3 sublineages. The remaining 0.03% of positive samples contained the Delta AY.4 variant.

Recombinant variants

The analysis also detected a small number of cases of recombinant variants of the original BA.1 Omicron strain and BA.2. There were five cases of the XE recombinant variant, and three of the XL recombinant variant.

On 25 March, the UK Health Security Agency (UKHSA) reported 637 cases of XE in England, with the earliest case identified on 19 January. Using the most recent data up to mid-March, XE appeared to have a growth rate 9.8% higher that of BA.2, the UKHSA said in a technical briefing.

However, ICL scientists said that, because of the small number of recombinants in their sample, it was not possible to determine whether the variants were more transmissible than others.

Professor Paul Elliott, Director of the REACT programme, said: ‘These trends are concerning since, when a very high number of people are infected, this may lead to more people becoming seriously ill and needing to go to hospital.’

Dame Jenny Harries, Chief Executive of the UKHSA, said: ‘These latest study results are another reminder that the pandemic is not over, and there is still a real risk to many of us catching COVID-19 with infection rates so high.’

Round 19 was the final report of the REACT-1 study following the Government’s decision to withdraw funding. Other research into COVID-19 prevalence, including the ZOE COVID study, has also lost its funding.

The preliminary results from round 19 of REACT-1 are being submitted for peer review.

This article originally appeared on Medscape, part of the Medscape Professional Network.


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