June 17, 2021 --The number of people infected with the coronavirus in England has increased rapidly, with most infections happening in children and young adults who have not received a vaccine, according to new research.
Results from an ongoing study show that an estimated 0.15% of people had the virus, or around 1 in 670
The data was based on 108,911 self-administered PCR tests collected from May 20 to June 7, 2021
The research team, led by researchers from Imperial College London, reported that national prevalence of the virus has increased from 0.10%, or around 1 in 1,000, since its previous survey in the second half of April to May 3.
The Rise of Delta
The study found a rapid replacement of the Alpha (B.1.1.7) variant of the virus with the Delta (B.1.617.2) variant. The authors noted that infections from the Delta variant, which was first identified in India, are doubling every 11 days in England
"These data coincide with the Delta variant becoming dominant and show the importance of continuing to monitor infection rates and variants of concern in the community," said Paul Elliott, and professor and director of the study program.
The preprint study – which has yet to be peer reviewed -- suggested that the link between infections, hospitalizations, and deaths had been weakening since February because of the country’s vaccination efforts. However, since late April, that trend had been reversing for hospitalizations.
The highest rate of infections was seen in young people age 18 to 24, followed by children age 5 to 12.
Although prevalence in people under the age of 50 was 2.5 times that of those aged 50 and above, infections appeared to be growing at a similar rate in both groups, the scientists found.
"Even though we are seeing the highest infection prevalence in younger people who are less susceptible to COVID-19, if this growth continues it will drive up infections in older, more vulnerable people, as the vaccines are not 100% effective and not everyone has been fully vaccinated,” Steven Riley, professor of infectious disease dynamics at Imperial College London, said
"This would lead to more hospitalizations and deaths, and risks straining the [Natnoial Health Service], which is why it's vital that people take up their vaccine offer and continue to stick to the rules,” he added.
The latest data also shows substantial regional variations across England. The highest prevalence was found in the North West. The South West, meanwhile, had the lowest.
Commenting on the study for the Science Media Centre, James Naismith, a professor and director of the Rosalind Franklin Institute and University of Oxford, predicted "a further cycle of doubling further down the road,” although the summer would "help blunt its growth.”
With the exception of the Delta variant, "we would have been able to end restrictions with almost no risk as originally planned,” he said.
"It must be understood that without vaccines, the Delta variant would have been a disaster for the U.K.," leading to a shutdown of society "or health care collapse,” he added
"These findings highlight the stark context in which we took the difficult decision to delay step 4 of the roadmap out of lockdown,” said Matt Hancock, England's Health Secretary.