Half of us may have virus as deaths hit 422
THE UK death toll reached 422 yesterday as a study suggested that half of Britons could already have been infected with coronavirus.
Modelling by researchers at the University of Oxford found that if many people suffered few or no symptoms, large numbers could have unknowingly had the virus.
They said widespread antibody testing was urgently needed to determine the true scale of the UK epidemic. A total of 90,436 people in Britain have now been tested, with 8,077 confirmed positive. But the lack of testing for people who are not in hospital means scientists remain uncertain about the rate of infection.
The study, led by Sunetra Gupta, a professor of theoretical epidemiology, used estimates about the behaviour of the virus and case and death reports to examine possible infection rates.
Surveys
The results suggested that the virus could have begun spreading in the UK more than a month before the first case was reported.
If this were true, many Britons may theoretically have already developed immunity – raising the possibility that “herd immunity” could be reached.
Prof Gupta said: “We need immediately to begin large-scale serological surveys – antibody testing – to assess what stage of the epidemic we are in.”
The university’s Evolutionary Ecology of Infectious Disease group study was based on the assumption that only a small proportion of people are at risk of being hospitalised.
Results suggested fewer than one in a thousand people who contract Covid-19 need hospital treatment.
It contrasted strongly with previous research from Imperial College London, which warned of a catastrophic death toll without stringent social distancing measures.
A preliminary report on the Oxford findings said: “Our simulations are in agreement with other studies that the current epidemic wave in the UK and Italy in the absence of interventions should have an approximate duration of two to three months, with numbers of deaths lagging behind in time relative to overall infections.
“Importantly, the results we present here suggest the ongoing epidemics in the UK and Italy started at least a month before the first reported death and have already led to the accumulation of significant levels of herd immunity in both countries.” Government officials and their advisers have said a reliable antibody test would be a “game-changer”.
Unlike tests currently being used, they can show whether someone has previously had the virus and recovered, rather than just whether they are currently infected.
Knowing how the disease is spreading would help experts understand when social distancing measures could be safely relaxed.
Jonathan Ball, professor of molecular virology at the University of Nottingham, agreed that widespread antibody testing would help us understand the size of the epidemic.
He said: “This is interesting work, but is hampered by the same issues that impacts on all epidemiological models – they rely on assumptions that at the moment are based on only a paucity of scientific fact about how thus virus transmits.
“The reliable way to answer the really important question about levels of exposure is to carry out serologybased studies.
“This is key data as it tells us about the rates of serious disease and death, and will give an accurate idea of future waves of infection.”