Downing Street’s scientific advisers feared people might intentionally seek to contract coronavirus and that a black market in fake test results could emerge if employers allowed workers to return only when they had a positive antibody test. The Scientific Advisory Group for Emergencies, known as Sage, was warned last month by its behavioural psychology subgroup that the widespread introduction of antibody tests could lead to a range of potentially dangerous and even criminal “negative behavioural responses” if not handled well. The warning, discussed by Sage on 14 April, is among a tranche of official documents released on Tuesday as part of the government’s efforts to be more transparent about the advisory groups and the scientific basis for the advice they are giving ministers. The papers show that: • On 4 February, Sage estimated the size of the outbreak in China to be “at least 10 times higher” than the official number of confirmed cases. • On 3 March, as Boris Johnson described how he “shook hands with everybody” on a hospital visit, a Sage subgroup said ministers should advise against greetings “such as shaking hands and hugging”. • On 23 March, the day of the lockdown, Sage discussed how “hard-hitting” emotional messaging could be needed to make complacent people feel at risk. • Modelling discussed on 23 March predicted London’s intensive care unit capacity would be breached by the end of the month. The rapid rise of admissions to intensive care units meant a reproductive rate, R, of more than 3 could not be ruled out. • Easing the lockdown must be done extremely carefully and that a “traffic light system” could help people understand what activities were high or low risk. Antibody tests are expected to become available in the UK within the next month, but their value is still under debate. While most people who recover from Covid-19 are expected to have antibodies to the virus, it is unclear how protective they will be, and how long any protection will last, making many scientists cautious about “immunity passports” Experts on the scientific pandemic influenza group on behaviours, Spi-B, which feeds into Sage, explained in April that pre-emptive measures were needed to prevent a range of undesirable outcomes when antibody tests became available. The group described how people who tested positive might get sloppy with hand hygiene and contribute to the spread of the virus, or put themselves forward for jobs that exposed them to infectious people, a particular concern if the test result was faulty. The experts went on to warn that employers might discriminate against staff on the basis of their antibody tests and that if a positive test was needed to return to work, people might “game” the system and deliberately seek infection or try and buy fake test results. A second paper from the Spi-B experts warns that any attempt to cycle between periods of lockdown and easing would need to be explained extremely carefully to the public. After months of lockdown, people might assume that any easing of the restrictions meant the risk of infection had gone away. If infections then picked up and further lockdown was ordered, it was “likely to be seen as a serious failure of policy and trust in public health advice will be lost”. The documents do not provide complete transparency about the Sage group’s deliberations, however. The four-page paper from the Spi-B group on easing the lockdown includes more than a page of redacted material. Other papers reveal that the Covid-19 Genomics UK consortium, a group of geneticists charged with understanding the epidemic, swiftly identified 12 lineages of the virus in March, consistent with the virus being imported to the UK from Europe and “multiple locations around the world”. A further Sage paper agreed that stopping or reducing public transport would have a “minimal effect” on slowing the spread of the virus. Concerns that a London lockdown would lead to people leaving the city and spreading the virus elsewhere were dismissed because infections were already present outside the capital. On the day of the nationwide lockdown, 23 March, Sage considered a raft of measures that might be needed to ensure people complied with strict social distancing and the stay-at-home policy. It raised the prospect of new legislation to enforce social distancing and warned that people who were “complacent” about the virus needed to feel an increased level of “personal threat” which could be achieved using “hard-hitting emotional messaging.” Asked about the redacted material, a government spokesperson said: “The only redactions relate to comments made by a SAGE sub-group on the early development of policy still under consideration or to remove contact details. Redactions were carried out by officials working for the Government Office for Science in consultation with the department developing the policy.”