A 75-year-old woman in Nottingham was the first person to contract coronavirus in the UK, researchers believe.
The woman, who died after falling ill with the virus, provided a sample on February 21 – which later tested positive – after being admitted to hospital with severe breathing difficulties, researchers from the University of Nottingham say.
They made the discovery after analysing 1,660 samples from 1,378 patients that were collected between January 2 and March 11 from a Nottingham teaching hospital for routine diagnostic investigation.
Writing in a study which has not yet been peer-reviewed, the researchers say: "Patient 1 in this study is, to the best of our knowledge, the earliest described community-acquired case of SARS-CoV-2 in the UK, admitted to hospital care on the 21st of February 2020."
DNA sequencing showed there had been multiple introductions of the virus into the region before wide-scale testing was introduced.
It also reveals the first official case of coronavirus in the area – a traveller who had returned from South Korea and tested positive on February 28, had most likely caught the virus in Nottingham rather than in Korea, as had been assumed.
Researchers say the overall findings of their study indicate the early spread of Covid-19 could have been prevented if initial case definitions had been less stringent and extensive community testing had been in place sooner.
The results suggest the virus was already circulating widely in local communities in the UK in early February and into March, and was undetected because of restrictive case definitions that informed testing policy at the time, they add.
Initially, Covid-19 testing in the UK required a strict criteria to be met, specifically a recent travel history to China's Hubei province or contact with a known case and one or more of fever, shortness of breath or a new and persistent dry cough.
This criteria was revised on several occasions to include travel to mainland China and several other Asian countries, then expanded further to include Iran and northern Italy, before finally being removed as essential criteria for diagnostic testing by mid-March.
The researchers' intensive sequencing of virus strains circulating through March – when there was limited community testing – showed numerous introductions of different strains of the virus that went undetected.
Professor Jonathan Ball, one of the authors of the study, said: "Our data highlights the importance of timely and extensive community testing to prevent future widespread transmission of the virus.
"Had the diagnostic criteria for Covid-19 been widened earlier to include patients with compatible symptoms but no travel history, it is likely that earlier imported infections would have been detected, which could have led to an earlier lockdown and lower deaths.
"However, the capacity for testing available nationally was not sufficient at the time to process the volume of testing required with a broader case definition.
"In order to prepare for any future pandemic such as this, the UK urgently needs to invest in and expand diagnostic capacity within NHS and PHE (Public Health England) diagnostic laboratory services.
"Any lasting investment in the human resources and associated infrastructure to achieve a more agile epidemic response both nationally and globally will undoubtedly save lives and drastically reduce the adverse impact of such outbreaks on the economy."