The number of COVID-19 infections is doubling every nine days in England, according to a large-scale population swab survey that estimates around one million people are harbouring the virus.
According to the study authors, “the second wave of the epidemic in England has now reached a critical stage.”
However, scientists say the results do not reveal the impact of recently introduced measures due to a time lag.
The lowest prevalence is in the eastern and southern parts of the country, including London.
The REACT-1 study, carried out by Imperial College, uses nose and throat swabs collected from 160,000 people over a two-week period, and then does a PCR test on them in a lab.
The researchers, however, chose to publish the results from only half of the number of planned swabs, in today’s “interim report,” meaning the data was made public earlier.
The results showed that 1.28 of participants had the CCP virus, with an “R number” of 1.56 nationwide, indicating a national doubling time of 9 days.
“Based on our prevalence estimate at the national level of 1.28 percent, we estimate that 960,000 ... individuals are harbouring SARS-CoV-2 virus in England on any one day,” said the report.
Assuming that the virus can be detected 10 days after infection, that corresponds to 96,000 people becoming infected each day.
“It’s too early to tell whether recent stricter measures are having an effect, which is why continued monitoring is vital to understand what works and adapt responses accordingly,” said Riley.
Hunter said that the results confirm those of other major studies, which together point towards a rapidly increasing epidemic. “But because of the lag between becoming infected and developing a positive test such data does not necessarily tell us what may be happening now with recent changes in restrictions,” he added.
The study showed an increase in positive tests across all ranges. The highest level of infections in different age brackets is still in the 18–24 age range, but the rate is growing fastest in the 55–64 age range.