Probably one in five people in England had a coronavirus, a new model suggests, equivalent to 12.4 million people, rising to nearly one in two in some areas.
It means that across the country as a whole the true number of people infected so far could be five times higher than the total number of known cases according to the government’s dashboard.
In some areas, however, the difference may be even greater. Parts of London and south are thought to have had up to eight times the number of cases detected so far.
The analysis, by Edge Health, reveals that the true number of coronavirus diseases in England could be as high as 12.4 million, equivalent to 22% of the population, on 3 January.
The government’s trial and detection program had detected 2.4 million cases by the same deadline.
The model estimates the number of cases in an area by comparing the number of deaths against an estimated mortality rate. It assumes a three-week delay between recorded cases and any associated deaths.
The findings say more than 10% of residents in 138 of England’s 149 high-level local authorities have contracted the disease.
Diseases in England could be five times higher than official figures
Official cases, listed compared to cases considered in England
% of English population with coronavirus infection over the pandemic, up to 3 January 2021. Data: Estimates, Edge Health. Recorded cases, data.gov.uk.
The model suggests that two out of five people were caught in six local authorities in London and the south-east: Barking and Dagenham, Newham, Thurrock, Redbridge, Havering and Tower Hamlets.
It is estimated that there were over 100,000 coronavirus infections each in the Barking cities of London and Dagenham and Newham, approximately 54.2% and 49% of their numbers.
Official figures from Public Health England show that just under 14,700 cases were recorded in Barking and Dagenham and just under 21,700 in Newham by 3 January.
According to the model, four northwest local authorities, which were hit harder at the start of the second wave of the pandemic, were among the 10 worst affected local authorities: Liverpool with 38.8% infected, Manchester 38.6 %, Rochdale 38% and Salford 37.8%.
One in two people in the worst-hit areas of England may have had a coronavirus
Official cases, recorded against local authority speculative cases.
% of people with coronavirus infection over the pandemic, up to 3 January 2021. Data: Estimates, Edge Health. Recorded cases, data.gov.uk.
The estimates are in line with accepted experience that the true number of diseases is likely to be much higher than the number of recorded cases due to asymptomatic cases and test failure to exclude all cases. This is especially true at the onset of the pandemic when the UK diagnosis system was much poorer.
Official government data on recorded cases to date shows that Merthyr Tydfil, Blackburn with Darwen and Blaenau Gwent have the highest rates of reported cases, but new estimates show published case figures. much lower than the “true” rate of disease.
Daily test capacity stood below 40,000 for the first half of April, while it is now over 500,000.
The modeling shows that Newham, Reading and Barking and Dagenham have each seen nearly eight times as many diseases as official record figures show.
Estimates are more than five times the official number in 77 areas of England – just over half of the 149 high-level local authorities surveyed.
George Batchelor, co-founder and director of Edge Health, said: “Reported tests are only a small part of the picture of overall disease, which shows how bad London and the north west have been at the time. pandemic. It is inconceivable that the level of understanding of where and how diseases occur is not greater at this stage, as it would allow control measures to be more focused.
“Even with nearby vaccines, developing this understanding is crucial for the effective control and management of future variations of the virus. ”
exploratory record
The areas with the lowest overall disease rates are in the southwest: Devon with 5.9%, Dorset 5.8% and Cornwall 4.8%.
Edge Health estimated overall cases by looking at Covid-related deaths at each local authority as published by the Office for National Statistics and the Infectious Mortality Ratio (IFR).
The IFR is calculated by looking at the local authority age profile and applying age-specific mortality ratios from Cambridge University research. These infectious mortality rates are slightly lower for the second wave.
Once these two metrics are known, the researchers can estimate the number of cases on a single day by scaling the number of deaths within 18 days – used here as normal time between recorded disease and death – depending on the fatal death of an area. ratio. The model number of cases is then extended to the present day by assessing how test detection rates have changed over the past three months.
The modeling takes into account the issues, deaths and age structure of an area, but does not look at other factors such as poverty.
Karl Friston, a professor of neuroscience imaging at University College London and a spokesman for the Independent Sage group with special responsibility for modeling, said: “Roughly speaking, the number of new cases per days between four and eight times the number of cases diagnosed. ”
The UCL modeling itself was strongly linked to the Edge results, leading Friston to say that there was “pleasant compatibility” between the two models.