Rival groups of scientists are at loggerheads over how government should handle the Covid pandemic, with one advising that only over-65s and the vulnerable should be shielded, while the other backs nationwide measures. The conflicting advice to the UK government and chief medical officers (CMOs) came in two open letters issued on Monday by the rival camps. It came as Prof Chris Whitty, England’s CMO, and the chief scientific adviser Sir Patrick Vallance made a national TV broadcast to set out the risk of the virus spreading exponentially, with a corresponding increase in cases and deaths, if public behaviour does not change. Thirty-two scientists signed one letter warning the government is heading down the wrong road and must reconsider its policy to suppress the virus, adopting a targeted approach instead. Prof Sunetra Gupta and Prof Carl Heneghan from Oxford University, Prof Karol Sikora from Buckingham and Sam Williams of the consultancy Economic Insight issued their warning, with 28 other signatories, to the prime minister, chancellor and the UK’s four CMOs. Support for the CMOs and Vallance, who appear to be advocating greater restrictions, came from a letter signed by second group of scientists, headed by Prof Trisha Greenhalgh at Oxford University and backed by 22 others. “We strongly support your continuing efforts to suppress the virus across the entire population,” they say, in what will be seen as a rebuttal of Gupta and colleagues. Segmenting the population and shielding the elderly until herd immunity has developed will not work, they add. The two stances underline a schism within the scientific community over how to tackle the second wave of coronavirus in the UK. The Gupta-Heneghan-Sikora letter warned that imposing lockdowns and restrictions wherever case numbers rise and potentially across the whole of the country is “leading to significant harm across all age groups, which likely offsets any benefits”. “The existing policy path is inconsistent with the known risk-profile of Covid-19 and should be reconsidered. The unstated objective currently appears to be one of suppression of the virus, until such a time that a vaccine can be deployed. This objective is increasingly unfeasible,” they add. Gupta and colleagues say we should think beyond coronavirus, taking account of the deaths that will occur from other causes because people are too anxious to go to their doctor or the NHS cannot treat them. And we should think about the economic and social impact of lockdowns. “Blanket Covid policy interventions likely have large costs, because any adverse effects impact the entire population,” they say. Asked what would be an acceptable level of Covid deaths under this scenario, Williams said: “That’s not so much how we would think about it.” There were avoidable deaths from other causes during the lockdown. “You have to be quite sure you are going to save lives if you take measures that will cost them,” he said. They say the focus on case numbers and the R number (showing the rate of infection) is wrong and they are subject to interpretation, with outcomes mattering, not case counts. Deaths are mostly in the older population: 89% are in the over-65s and 95% in people with pre-existing medical conditions. “The harm caused by uniform policies (that apply to all persons) will outweigh the benefits,” they write. Those at risk should be told, so that they can make their own decision about their safety. “Give the public honest and objective information about the risks they face,” Williams said. Instead, the dangers for everyone had been talked up, making people with low risk factors more scared than they should be. The second letter, from Greenhalgh and colleagues, says that deaths and severe illness have occurred in all age groups. They argue that “long Covid” – extended and debilitating illness – has affected tens of thousands of people in the UK, many of them young. They say it is not practical to cut off a cohort of vulnerable people from the rest in an open society “especially for disadvantaged groups (e.g. those living in cramped housing and multi-generational households). Many grandparents are looking after children sent home from school while parents are at work.” They share the desire of the public to return to “normality”, but it must be balanced with variable restrictions to control the virus “which respond to the day-to-day and week-to-week changes in cases. “Normality” is likely to be a compromise for some time to come. Some of the authors are members of Independent Sage, a group that established itself because of concerns over the transparency of the government’s own scientific advisory committee on epidemics, which is chaired by Whitty and Vallance. The science itself cannot be definitive, they acknowledge. “Whilst it is always helpful to have more data and more evidence, we caution that in this complex and fast-moving pandemic, certainty is likely to remain elusive. “A research finding that is declared ‘best evidence’ or ‘robust evidence’ by one expert will be considered marginal or flawed by another expert. It is more important than ever to consider multiple perspectives on the issues and encourage interdisciplinary debate and peer review,” they say.