Researchers have warned that Covid-19 test data is likely to have under-represented the true extent of the virus in the UK during the peak of the outbreak – with the number of suspected cases observed by GPs potentially three times higher than official figures.
A study of data during the pandemic's peak from 157 practices in east London found GPs recorded more than 8,985 suspected cases between 14 February and 30 April.
The figure is triple the number who had their infections confirmed at test centres over the same period, according to the study led by London’s Queen Mary University and published in the British Journal of General Practice.
Lead author Dr Sally Hull said: "Our results suggest that Covid-19 prevalence during the peak of the epidemic was higher than previously thought.
"The official Covid-19 test statistics are likely to have under-represented the extent of the epidemic, as many people with Covid-19 would not have been tested, including those with milder symptoms or those who could not access testing centres."
Looking at anonymised data from the records of around 1.2 million adults registered in four east London boroughs, the study found those with dementia were seven times more at risk of developing suspected coronavirus.
And, unlike other studies, it found that women were at a "slightly" increased risk of becoming infected with suspected coronavirus compared to men. Researchers said the data suggested the known risks to men "emerge later in the disease trajectory”.
Meanwhile, scientists found that ethnic minority adults were twice as likely to present with suspected coronavirus than white adults – and that this was not necessarily due to other factors such as health conditions, obesity or social deprivation.
In the four boroughs studied, three were in the top five London areas for coronavirus fatalities. In total 55 per cent of the population of assessed areas came from ethnic minorities.
Dr Hull added: "The high prevalence among black, Asian and minority ethnic patients remains a big concern and we now know that ethnicity is still a risk factor even after you take account of social deprivation, long-term conditions and body mass index.
"So there is something else driving this, which urgently requires more research."
Additional reporting by agencies
