Relaxing restrictions at a time when the 'R' rate in the UK remains well above one leaves the country exposed to an 'unpredictable' risk around the potential emergence of dangerous new strains that could go on to increase the impact of the pandemic worldwide, the researchers warn.
Writing in the journal Virulence, the researchers warn that 'the laissez-faire approach that many governments are now taking towards COVID-19 management, risks substantially increasing mortality and morbidity in the wider population'.
The 'R' rate in the UK is currently around 1.2-1.4 - and the study warns that restrictions such as mask wearing can only safely be relaxed once it falls below 1, meaning that the spread of the virus is shrinking.
Despite a fall in new cases reported UK-wide in recent days, there have still been around 200,000 new cases reported in the past seven days alone.
The study warns: 'The risk associated with large scale natural infection is not predictable because we cannot know the virulence characteristics and vaccine susceptibility of the new variants that will continue to evolve.
'With an increasing number of people being infected, the rate of new variant evolution of SARS-CoV-2 accelerates, increasing the likelihood that SARS-CoV-2 variants will acquire higher virulence and vaccine escape potential.'
Lead author and editor in chief of Virulence, Professor Kevin Tyler from the University of East Anglia’s (UEA's) Norwich Medical School, said: 'Over the past 17 months, economies, education and mental wellbeing have suffered tremendously due to the restrictions imposed in an attempt to stem the spread of the pandemic.
'Although vaccines have weakened the link between infection and mortality, they should not be used as an argument to justify a broad change in policy for countries experiencing an exponential increase in infection numbers.
'Relaxing restrictions boosts transmission and allows the virus population to expand, which enhances its adaptive evolutionary potential and increases the risk of vaccine-resistant strains emerging by a process known as antigenic drift. Put simply, limiting the spread of COVID-19 as much as possible restricts the number of future deaths by restricting the rate with which new variants arise.'
He added that new strains could also pose a greater risk or be more transmissible in unvaccinated parts of the population such as children - warning that it could become necessary to widen the vaccination campaign to children to prevent the spread of these new variants.
Co-lead author and evolutionary biologist Prof Cock Van Oosterhout, from UEA’s School of Environmental Sciences, said: 'We have an arms race on our hands.
'On the human side, the arms race is fought with vaccines, new technology such as the NHS COVID-19 app, and our behavioural change, but the virus fights back by adapting and evolving.
'It is unlikely we will get ahead in this arms race unless we can significantly reduce the population size of the virus.'
The study warns that 'new variants could rapidly replace existing strains, particularly during the exponential growth phase of the infection' - and warns that public health policies proven to slow the spread of COVID-19 must be maintained.