London: Over 25 per cent of people in Britain are likely to have had COVID-19 already, according to a study released on Thursday by the University of Manchester.
Researchers from the University of Manchester, Salford Royal NHS Foundation Trust and Res Consortium used the published local authority data to assess the cumulative impact of infection since the COVID-19 outbreak began in Britain, the university said, Xinhua news agency reported.
It enabled the researchers to calculate the R-value -- the number of people infected by one person with COVID-19-- within each local authority area.
Published case data from 144 local authorities analyzed by the team now gives an R value of well below one, according to the university.
The value -- which was over three at the start of the outbreak in the middle of March 2020 -- fell as a consequence of social distancing combined with the natural consequences of cumulative community infection, according to the university.
By the second half of April, based on extrapolating the variation in infection rate between local authorities with more or less cases reported depending on location, over 25 percent of Britain's population could already have had the novel coronavirus, the team have found.
"COVID-19 is a highly infectious condition and very dangerous for a small group of people. However a much larger group seem to have low or no symptoms and have been unreported," one of the authors of the study Adrian Heald from the University of Manchester said.
"We show how effective social distancing and lockdown has been. Though this is a tragedy, it could have been far worse," said Heald.
Mike Stedman from Res Consortium who carried out the data analysis said, the figures are "not perfect", and only extensive antibody testing "could give us a more accurate picture".
"As that is only just becoming available, we believe this form of modelling is important in informing the best approach to unlocking the population," said Stedman.
The authors argued that incremental lifting of current social restrictions as soon as possible is vital to minimize further damage to the economy and the impact of prolonged social containment.
However, they added, this must be balanced against containing the current pandemic and minimizing future waves of infection.
Meanwhile, the World Health Organisation (WHO) on Thursday predicted less number of COVID-19 infections in Africa and forecast a slower peak in most countries following growing success of anti-infection measures.
Matshidiso Moeti, WHO regional director for Africa, said the revision is based on the success of some of the measures that governments are implementing, like partial lockdowns, social distancing and washing of hands, Xinhua news agency reported.
She said an earlier modelling developed by the WHO had shown that COVID-19 cases in Africa were to peak in five weeks after the first case was detected in a country and that on average, 26 percent of the entire population in the continent would have been infected.
"This modelling was based on projected community infections including especially in the rural areas. But we have seen that African governments have put in place measures that have slowed infections," she said during her weekly online update to journalists.
(IANS)