The government’s £100bn Operation Moonshot mass Covid testing scheme is like “building a Channel tunnel without asking civil engineers to look at the plans”, experts have warned. They say there is no evidence the plan will offer any benefit, the effectiveness of the tests it uses is weak, and the programme itself has been structured without input from the body responsible for advising ministers on screening strategy. “It worries me that ministers … can wake up one morning saying let’s spend £100bn on this and not have it scrutinised – it would be like building a Channel tunnel without asking civil engineers to look at the plans,” said Dr Angela Raffle from the University of Bristol, who is also a consultant to the UK national screening programmes. “For screening to work, you would have to do it on literally everybody every few days,” she said. “When I learned of the Moonshot proposal – this seemed to me to be the most unethical proposal for use of public funds or for screening that I’d ever seen.” The plans for Operation Moonshot, which aims to screen millions of asymptomatic people every week, with a budget of £100bn to deliver 10m tests a day, emerged in September. It is being piloted in Liverpool and a more targeted approach to screening is expected to begin in universities, towns and cities in the coming month. The strategy is envisioned as a way of getting workers back into offices, allowing families to hug their loved ones again in care homes and perhaps even creating the possibility of a near-normal Christmas. As yet there is no evidence on whether screening the general population for Sars-CoV-2 – the virus that causes Covid-19 – will increase or decrease disease transmission, hospitalisation and death, the experts cautioned. At the heart of the issue is the Innova lateral flow test, made by a California-based company, which has been awarded two contracts by the UK government and is being deployed in Liverpool. Last week, the Department of Health and Social Care said the test had an overall sensitivity of 76.8% for all PCR-positive individuals (PCR is the gold-standard swab test that is widely used but requires lab processing). But that sensitivity is based on tests administered by experienced research nurses – the percentage falls to 57% when administered by self-trained staff, akin to what is happening in Liverpool, said Jon Deeks, a professor of biostatistics at the University of Birmingham. “The fact that difference exists is very worrying because it sort of suggests that this test is quite fickle,” he said. “The fact that this test is missing cases means that people who have negative results are still at risk of having Covid-19 and this message is not being given to them,” he said. Allyson Pollock, a clinical professor of public health at Newcastle University, said: “That is one of the myths that’s being propagated … that you could have your test in the morning – and if you were negative you could go about your business or go to funerals, or go to the nursing homes, and you’ll be fine.” On the other hand, the data on false positives from the test is encouraging. Only 0.38% of the Covid-positive tests are wrong, Deeks noted, cautioning that those small percentages can add up when testing large swathes of the population. Another point of contention is the ability of the test to detect infectiousness – whether an individual is transmitting the virus. “The arguments that we’re hearing …that this test can tell the difference between infectious and non-infectious is not substantiated by any data,” Deeks said. The process of screening also includes the intervention of contact tracing, part of the £12bn test-and-trace system that has been widely criticised for its limited effectiveness. Additionally, survey data suggests the extent to which contacted people are self-isolating is low. “The government has already spent £12bn, it’s now proposing to spend the equivalent of around 70% of the entire annual NHS budget on Operation Moonshot running it up to the whole population,” said Pollock. “You won’t just have to have one test, you may end up having to have multiple tests, which is exactly why the Japanese decided to abandon the idea. So, our big plea is that we really need to get the contact tracing element working.”