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There are early signs that England’s second lockdown is reducing Covid infection rates, a prominent scientist has said, cautioning that it is too soon to say how low they will be by early December.
The extent to which the current measures suppress the spread of the virus is likely to determine how tight restrictions will be after 2 December, when the lockdown is expected to end, and whether there is scope for any relaxation in restrictions around Christmas.
Prof Neil Ferguson, an expert in modelling disease outbreaks at Imperial College London, who resigned from the government’s Scientific Advisory Group for Emergencies (Sage) in May, pointed to both pillar 2 case data – testing in the community – and new admissions to hospital as markers of a potential impact.
“There is evidence that infection rates are plateauing and may be starting to go down slowly,” he said.
He said these trends could be attributed to lockdown measures, although cases were already slowing somewhat due to the effect of tier 3 restrictions in some parts of the country.
“It is too early to assess what the overall impact by 2 December will be, though we should not expect too much, given schools are still open,” he said. “A halving of infection prevalence over the four weeks would be a positive result.”
Ferguson said that deciding what control measures were introduced after lockdown was lifted would be key.
“We now have clear evidence that tier 3 measures were working to bring down infection rates in some areas. Tier 2 was also having an impact, but a smaller one,” he said. “The decision is a political one, but if we don’t want to see infection levels rebound from 3 December, my assessment is that measures between tier 2 and tier 3 will be necessary in the great majority of locations.”
The lag between restrictions being introduced and their effects on the number of cases becoming apparent is down to a number of factors.
It generally takes about five days between someone becoming infected and showing symptoms – although it can take up to 14 days – with a test only recommended once symptoms have developed. It can then take a couple of days to receive test results, said Ferguson, while approximately a week of data is needed to see a trend.
It can take about two weeks before those infected deteriorate to the point of requiring hospital care, with more time generally passing before death occurs.
At present, data on infections in the community from a survey of randomly selected households, performed by the Office for National Statistics, is only available to 6 November and hence does not yet reveal the impact of lockdown.
Government data on cases by date reported reveals 20,291 people in England were reported as testing positive for coronavirus on Thursday. That is up from 17,189 on 18 November – breaking a six-day run of falling case numbers. However, unlike the ONS survey this data can be influenced by levels of testing available in different areas.
Over past two weeks hospital admissions have grown, although there are some signs they may be growing at a slower rate than previous weeks.
“Looking at the data by day of specimen, we have only had one full week reported since the start of the lockdown,” said Prof Steven Riley, co-author of the React-1 study and also from Imperial College London. “Given the speculation about a possible increase in social contact just prior to the lockdown, we need the data for this week before we start drawing conclusions.”
According to a Guardian analysis of case numbers by sample date from the government figures up to 14 November, the only English regions where cases are falling week on week are the north-west and north-east and Yorkshire – a pattern that suggests the falls are probably a result of the tier 3 restrictions that were already in place before the national lockdown.
“It is genuinely a bit too soon to tell whether lockdown is working, but the effect of lockdown 2.0 is certainly lagging its predecessor,” said George Batchelor, a co-director of Edge Health, which helped compile the data. “Aside from schools and universities remaining open, casual observations would agree this is not a lockdown like the first one.” .
Batchelor said any effect of the latest lockdown on hospitalisations, or deaths, would take even longer to emerge. “The primary focus of the government and Sage is ensuring that the second wave of Covid does not overwhelm the NHS. However, as we described when lockdown was introduced, the NHS is generally the last to feel the benefit of greater social distancing and reduced transmission.”
London and the south-east in particular are yet to experience this impact, with both regions’ three-day average for cases on 14 November up by a quarter compared with the week before. Hospital occupancy and ventilator use were also up by over a quarter week on week in both regions.
Prof Christina Pagel, director of the clinical operational research unit at University College London and a member of the Independent Sage group of experts, said: “England overall is going down, but only because of the north-west.
“The next few days will be really important to see what is happening [in London and the south-east] because it should be coming down this week – and if it is not coming down this week then that’s a problem.”
Source: The Guardian
Keyword: Covid lockdown shows signs of working in England, expert says | World news