The unintended consequences of the UK lockdown and why millions of people could already be infected
The scientific advice on which the Government has based its coronavirus strategy has been released, giving a grim insight into the expected progression of the virus and calling into question some of the strategies. Documents studied by the Scientific Advisory Group for Emergencies (Sage) showed that social-distancing “lockdown” measures to keep people apart may need to be in place for most of the year to control the spread, and millions may already be infected, according to worst-case modelling. The Government published the advice after Boris Johnson, the Prime Minister, said he expects the tide to be turned in the fight against Covid-19 within 12 weeks. Yet modelling shows the crisis could last far longer, with the virus potentially returning next winter. Many of the measures enacted may also have unintended consequences. Here is what we now know.
The number of Britons who have already been infected by the virus may be anywhere up to 23 million, new modelling suggests. Calculations by the London School of Hygiene and Tropical Medicine (LSHTM) estimate that, for every single death, many more cases are likely to be present in the population. Health experts are increasingly concerned that hundreds of thousands of people may be infected with a mild form of disease without even knowing it, and could be inadvertently spreading the virus (the so-called “super spreaders”, see video below) while they think they are healthy.
The Department of Health is keen to roll out an antibody test that could tell if someone had already been infected and built up immunity, meaning they would no longer need to adopt social isolating or distancing measures. The team at LSHTM ran 25,000 epidemic simulations for different death and infection rate scenarios ranging from 1.5 to 10 per cent death rate in the population and someone infecting between one and three people. For a scenario with a death rate of 1 per cent, where each infected person infects three more – which is closest to what is currently thought to be happening – the team at LSHTM found that one death points to a minimum of 37 cases, a maximum of 138,624 and a median average of 1,733. With the current number of deaths at 167, it means that between 6,179 and 23 million people could already be infected, with an average of nearly 290,000.
Scientists at the Universities of Oxford, Warwick and Lancaster found that contact tracing could reduce the transmission rate from 3.11 people to 0.21 – enabling the outbreak to be contained. They carried out a postal and online survey, asking 5,802 people how many social interactions they had on a given day and found the average number of contacts over a 14-day period was 217. Of these total encounters, an average of 59 contacts (27 per cent) met the definition of a close contact (within two metres for 15 minutes) and 36 (61 per cent) could be traced. However, the team said that even with contact tracing, they would still expect 15 per cent of all infected people to generate at least one case that could not be identified. Separate modelling by the LSHTM also found that if an infected person infected another 1.5 people, tracing fewer than 50 per cent of contacts was enough to control the outbreak. However, once it reached an infection rate of 2.5 people, health officials would need to trace 70 per cent, and by 3.5 people, they would need contact nine out of 10 people that the infected person had met. The team at LSHTM also found that tracing and isolation was only feasible when fewer than 1 per cent of transmissions occurred before the onset of symptoms. Currently there is no data on how many people are becoming infected before symptom onset. The team concluded that “highly effective contact tracing” and case isolation is enough to control a new outbreak of Covid-19 within three months.
Modelling from the Universities of Exeter, Bristol and Warwick showed that, without any measures, the epidemic would have peaked around 133 days after the first person-to-person transmission in Britain, which occurred around Feb 28. So without intervention, coronavirus would have peaked in late June to early July. The research teams also found that an outbreak starting in Brighton, or the South East England, would peak in London and the South East first, with North East England, Yorkshire and Humber and Wales following with a 10-day lag.
New research by Imperial College London found that people suffering from coronavirus may experience a wide range of symptoms, not simply a fever and a dry cough. Other symptoms included fatigue, fever, chill, headache, diarrhoea and nasal congestion. A few cases also suffered confusion, dizziness, nausea, difficulty walking and vomiting. The team looked at 107,000 cases from mainland China, Hong Kong, Japan, Singapore and South Korea. They found that among people hospitalised from the onset of symptoms, patients developed pneumonia within five days, and needed ventilation within eight days.
The closure of schools and other public venues actually risks inadvertently spreading coronavirus, Sage behavioural scientists warned the Government. House parties and rendezvous in parks were among the scenarios predicted as a result of a lockdown. Longer queues in takeaway shops were also warned about. In a document dated March 4, the Scientific Pandemic Influenza Group on Behaviours (SPIG-B) conceded: “Empirical evidence for the behavioural and social impact of, and adherence to, each of the strategies is limited. We are not aware of any evidence on their interaction.”
On Thursday, March 19, the Prime Minister told the nation: “I think, looking at it all, that we can turn the tide within the next 12 weeks and I’m absolutely confident that we can send coronavirus packing in this country.” Up until Wednesday, March 18, the Government’s policy had been to keep schools open, partly to ensure that key NHS and other frontline care workers could remain in work rather than having to take time off to care for children. However, Mr Johnson said the Government was forced to change tack because the rate of Covid-19 infections was increasing faster than anticipated.