Coronavirus cases were at least three times higher than the Government was reporting at the height of the UK’s crisis, data suggests.
Analysis of thousands of GP appointment records show there were 8,985 suspected Covid-19 cases between February 14 and April 30.
This is the number of people who family doctors thought had Covid, but could not diagnose them without a test.
It was triple the number of people who tested positive at Government swabbing centres over that same time period.
People who were suspected of having coronavirus before May were told to self-isolate and were not always given a test.
Swabs were reserved for hospital patients, the most ill, due to a shortage at the time and only NHS and care home workers were invited to drive-through centres for a test. It means the true scale of the outbreak remains a mystery to this day.
The latest analysis, by researchers from the Queen Mary University in London, only looked at suspected patients in parts of the capital.
It means the study likely only scratches the surface of the true number of infections at the time.
Researchers looked at data from the primary care records of about 1.2 million adults registered with 157 practices in four east London clinical commissioning groups in Newham, Tower Hamlets, Hackney, and Waltham Forest.
The four boroughs studied have went on to suffer some of the highest death rates in the country, meaning community transmission was likely rife at the time.
The researchers also found that black, Asian and minority ethnic (BAME) adults were twice as likely to present with suspected coronavirus than white adults.
BAME people have been disproportionately affected by the disease during the crisis, both in terms of infections and death rates.
Experts can’t pinpoint exactly why this is the case, but it could be down to the fact ethnic minorities are more likely to be poor, use public transport more often and work in public-facing jobs – all three of which make them more prone to interacting with strangers and catching the disease.
Patients with dementia were seven times more at risk of visiting their GP with suspected coronavirus, the records showed.
Older people have been the worst-hit by the virus and so they likely fell ill enough to have symptoms and go to their doctor.
Younger people probably caught the virus at the same rate, but most only experienced mild or no side effects.
Unlike other studies, the latest research found that women were ‘slightly’ more likely to go to their GP with suspected Covid-19 compared to men.
This goes against a mountain of data showing men are about twice as likely to fall unwell with the virus.
The researchers, led by Dr Sally Hull, from Queen’s, could not explain finding, but it may be that men were more likely to fall seriously unwell with Covid-19 and need hospital treatment, whereas women experienced mild illness and only went to their GP.
Dr 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.’
‘The high prevalence among BAME 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.’
Dr Hull said, moving forward, GPs need ‘timely reporting’ of test results to their practices and diagnostic information from NHS 111 to ensure patients with more severe episodes receive continuing care.
She said: ‘It’s going to be very important how GPs record and manage cases in their community, as this can provide an early warning system if cases are rising again in an area and if we’re about to see a second wave of infection.’
The results of the study have been published in the British Journal of General Practice.