COVID-19 prevalence in England rose to its highest level on record in October

A new study by researchers from Imperial College London has shown that COVID-19 prevalence in England rose to its highest level on record in October, led by a high numbers of cases in children and a surge in the south-west of the country.

Not only are the unvaccinated being vulnerable to the new surges that are caused by a variety of new emerging SARS-CoV-2 variants such as the Delta subvariant like AY.4.2 and other Alpha sub-variants, but breakthrough infections are also occurring in high rates among the vaccinated with some resulting in hospitalizations and even death.
 
The study team found that nearly 6% of school-aged children had COVID-19, although there was a drop in prevalence towards the end of the study’s period coinciding with the closure of schools for half-term holiday.
 
However, the study team warned that despite that dip, rates had doubled in older groups compared to September, a concerning sign as the government races to give booster shots to the most vulnerable.
 
The study findings were published in a preprint format. 

https://spiral.imperial.ac.uk/handle/10044/1/92366

The third wave of COVID-19 in England coincided with the rapid spread of the Delta variant of SARS-CoV-2 from the end of May 2021. Case incidence data from the national testing programme (Pillar 2) in England may be affected by changes in testing behaviour and other biases.

Community surveys may provide important contextual information to inform policy and the public health response. Methods: We estimated patterns of community prevalence of SARS-CoV-2 infection in England using RT-PCR swab-positivity, demographic and other risk factor data from round 15 (interim) of the REal-time Assessment of Community Transmission-1 (REACT-1) study (round 15a, carried out from 19 to 29 October 2021).

We compared these findings with those from round 14 (9 to 27 September 2021). Results: During mid- to late-October 2021 (round 15a) weighted prevalence was 1.72% (1.61%, 1.84%) compared to 0.83% (0.76%, 0.89%) in September 2021 (round 14). The overall reproduction number (R) from round 14 to round 15a was 1.12 (1.11, 1.14) with increases in prevalence over this period (September to October) across age groups and regions except Yorkshire and The Humber.

However, within round 15a (mid- to late-October) there was evidence of a fall in prevalence with R of 0.76 (0.65, 0.88). The highest weighted prevalence was observed among children aged 5 to 12 years at 5.85% (5.10%, 6.70%) and 13 to 17 years at 5.75% (5.02%, 6.57%).

At regional level, there was an almost four-fold increase in weighted prevalence in South West from round 14 at 0.59% (0.43%,0.80%) to round 15a at 2.18% (1.84%, 2.58%), with highest smoothed prevalence at subregional level also found in South West in round 15a.

Age, sex, key worker status, and presence of children in the home jointly contributed to the risk of swab-positivity. Among the 126 sequenced positive swabs obtained up until 23 October, all were Delta variant; 13 (10.3%) were identified as the AY.4.2 sub-lineage.

Discussion:

We observed the highest overall prevalence of swab-positivity seen in the REACT-1 study in England to date in round 15a (October 2021), with a two-fold rise in swab-positivity from round 14 (September 2021).

Despite evidence of a fall in prevalence from mid- to late-October 2021, prevalence remains high, particularly in school-aged children, with evidence also of higher prevalence in households with one or more children.

Thus, vaccination of children aged 12 and over remains a high priority (with possible extension to children aged 5-12) to help reduce within-household transmission and disruptions to education, as well as among adults, to lessen the risk of serious disease among those infected.