Science

Covid-19 spread may be levelling off in England, say experts


Community spread of Covid-19 in England may be levelling off even as some lockdown measures are relaxed, experts said following the release of official data.

Latest figures from the Office for National Statistics (ONS), based on household surveys, reveal that from 27 July – 2 August about 1 in 1,900 individuals had Covid-19, with 3,700 new cases per day.

The figures are lower than in the previous week (20-26 July), when about 1 in 1,500 individuals were thought to have Covid-19, with 4,200 new cases a day. But they remain higher than 13-19 July when 1 in 2,000 individuals were thought to be infected, with 2,800 new infections a day.

Gyms, salons and cinemas have been allowed to reopen, though bowling alleys, ice rinks and pilot sports events were all told a week ago to keep their doors closed amid fears in Downing Street of a surge in cases.

“Modelling shows rates of people testing positive for Covid-19 have risen since the lowest recorded estimate, which was at the end of June, but there is evidence that this trend may be levelling off when compared with last week’s headline estimate,” the ONS team report.

The government has also released the latest figures for the R value and growth rate, with the former at 0.8-1.0 for the UK and the growth rate at 0% to -5% per day. Last week the figures were 0.8-0.9 and -1% to -4% respectively. For an R of anything above 1, an epidemic will grow exponentially. Anything below 1 and an outbreak should fizzle out.

Both last week and this week, the R value for England was 0.8-1.0. For the second week in a row, the committee behind the figures said it does not have confidence that R is currently below 1 in England.

While at first glance this appears to suggest a less positive scenario than the ONS data, Prof Steven Riley, of Imperial College London, a member of the Scientific Pandemic Influenza Group on Modelling (SPI-M), said that, when looking at figures from the past few weeks, both point to the same conclusion: the spread of Covid-19 appears to be levelling off in the community in England.

Riley noted that the ONS figures draw on more recent data than the R value and growth rate – which rely more on hospitalisation and death figures – meaning the data applies to a slightly different period of time. Even so, the R value does not show a clear change in England.

“There are really three regimes: you can have high confidence [infections] are going down, that would be high confidence that R is less than 1; you can have high confidence that it is going up, that would be R is greater than 1; or the only thing left is not to be sure either way,” he said. “Levelling off is a really good description.”

Dr Sebastian Funk, an epidemiologist and member of SPI-M agreed, noting the uncertainty in the ONS estimates means the data is consistent with both and an increase and a decrease in new cases per day.

“With both the incidence and R estimates, there is no clear trend,” he said. “‘R could be above 1’ is not expressing any confidence in the fact that infections might be increasing.”

Dr Yuliya Kyrychko, a reader in mathematics at the University of Sussex, said that despite an apparent levelling off in new cases, infection remains quite prevalent in the community, noting in north-west and south-west England that the R value is possibly greater than 1 – although in the case of the latter, and London, there are too few infections for a robust R estimate.

“Recommendations on social distancing and other protective measures should continue to be followed to avoid a significant growth of infection in those regions,” she said. “This is particularly important in the context of expected large numbers of people going to beaches over the coming weekend due to continuing heatwave.”



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