The prevalence of coronavirus cases in England fell by about 60 per cent from February to March, and recent data suggest the decline is “leveling off,” the researchers said.
Experts found that the infection rate fell in all age groups and regions during those two months, and the figures also suggest that the introduction of a coronavirus vaccine could “break the link” between infections, death and hospital admissions.
According to the latest round of the Real-Time Community Disease Transmission Assessment Study (REACT-1), one in 500 people on average still carried the virus in March.
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The researchers found that from February to March, there was a “big drop” in the prevalence of the virus in southwest and London, but in the south of Yorkshire and parts of the east there are still “persistent areas of higher prevalence” of the Midlands and northwest viruses.
To date, more than 1.5 million people have given swabs for the REACT-1 study, so experts can estimate the rate of infection across the country. The tenth round of tests was conducted between March 11 and 30, with 140,844 smears collected, which gave 227 positive results. This compares with 689 positive results from 165,456 swabs from February 4 to 23.
The researchers’ findings, which have not yet been reviewed, were presented at a press briefing on Wednesday, April 7. They contained:
- The rate of community infection was 0.20 percent in March – up from 0.49 percent in February and 1.57 percent in January.
- Although on average there was a general decline in the prevalence of COVID throughout February and March, the researchers noted that last month’s data indicated that this had leveled off.
- Using only March data, it was estimated that reproductive number (R) – the average number of people to whom an infected person is likely to have transmitted the disease – 1.
- The prevalence of COVID-19 decreased in all age groups between February and March, with the highest prevalence now from 5 to 12 years, and the lowest in those over 65 years of age.
- In February and March, the number of foreign trips was “very, very low” on average compared to previous months.
- Comparing infections and deaths and hospital admissions, the researchers noted “fewer deaths per infection” than would be expected based on the last previous months of the study.
“The good news is that the prevalence has dropped by approximately 60 per cent from the previous round in February to current results which are now in March,” said Steven Riley, a professor of infectious disease dynamics at Imperial College London.
“The latest data do not show a continuation of the apparent decline, we have a leveling of prevalence, and this is reflected in the R estimate of 1. And we see some difference between our observed patterns of infection and death patterns from January, which we think probably suggests that mass vaccination that connection between infection and death. “
Commenting on data on infections, deaths and hospital admissions, he said: “We are seeing fewer deaths per infection than we would expect based on the last previous months of the study. To a lesser extent, we also see fewer hospitalizations per infection.
“We think this is a signal that the vaccination program is breaking the link, the previously strong link, between the pattern of infections and the pattern of death and hospitalizations.”
Riley warned that researchers would expect higher levels of infection if the vaccine slowdown slowed.
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“I think we’re starting to see the effect of the vaccine in our data, certainly in difficult outcomes,” said Professor Paul Elliott, director of the Imperial program at the School of Public Health.
He added that more work is needed to examine the impact of the vaccine on prevalence and transmission.
Elliott admitted that the “big drop” in the infection rate “leveled off” in March, but said it was “good news” that it had not increased with recent easing of restrictions, such as more permissible social interference and the return of students to schools.
He said that a “close briefing” was needed because the lock was further eased, and a “careful balancing procedure” was needed.