Boris Johnson remarked in 2007 that the true hero of the movie Jaws was the “laudable” mayor Larry Vaughn, who kept his seaside town open for business in spite of apparent hysteria around a series of shark attacks.
“A gigantic fish is eating all your constituents and he decides to keep the beach open,” Mr Johnson told a business audience. “It turned out he was wrong. But it remains that he was heroically right in principle.”
The prime minister, on the advice of his medical and scientific advisers, is trying to keep Britain open for business — at least for now — in the face of coronavirus, while around the world the shutters are being put up.
Mr Johnson, who said on Thursday that Britain was facing “the greatest public health crisis for a generation”, is facing criticism from some politicians and scientists for failing to act sufficiently swiftly or decisively against Covid-19.
By refusing to bow to political pressure to take drastic action now — such as by closing schools or isolating the elderly — Mr Johnson accepts that the disease will spread widely in society.
Some countries, such as Singapore or Hong Kong, have tried to quickly stamp out the disease with social distancing measures, but Patrick Vallance, Mr Johnson’s chief scientific adviser, said it was desirable to build up “herd immunity” in the population to protect the country in the longer term.
“About 60 per cent is the sort of figure you need to get herd immunity,” Sir Patrick told Sky News on Friday. That suggests up to 40m Britons might contract the disease under the government’s plan. As Mr Johnson concedes, many loved ones will die.
Since mid-February, as the virus morphed from a health issue into a national crisis, the prime minister’s chief adviser Dominic Cummings has helped to shape Mr Johnson’s approach, relying on scientific experts and communicating through simple messaging.
Mr Cummings has in the past expressed a personal interest in this topic. “I am particularly interested in public health and the field of epidemiology,” he wrote in 2016.
Both of the government’s three-word mantras for coronavirus came out of focus groups, a favoured tool of Mr Cummings. Following his success with “take back control” in the 2016 Brexit referendum and “get Brexit done” in the 2019 general election, two messages underpin Mr Johnson’s current strategy: “wash your hands” and “stay at home”.
The prime minister and his scientific advisers hope to manage the epidemic by “flattening the curve” of infection and delaying the peak until the summer, when the National Health Service will face less seasonal pressure.
Then — or so the theory goes — enough people will have acquired resistance to Covid-19 to avoid a second wave of disease next autumn or winter. Downing Street believes that other countries that have taken draconian action now will be vulnerable later in the year.
Mr Johnson’s strategy depends on building up the so-called herd immunity. If a high enough proportion has become resistant through Covid-19 infection, the virus will not have enough new people to catch and the epidemic will not be able to sustain itself. It will burn out.
But the idea is not scientifically proven to work for this new virus, where the long-term effect on the immune system is unknown.
Rupert Beale, who runs the laboratory for cell biology of infection at London’s Francis Crick Institute, a biomedical research centre, said: “The problem is we don’t know if herd immunity can be achieved. Other coronaviruses can reinfect a few months down the line. We don’t know yet for Covid-19.”
Most medical experts say that no one will be able to assess the strength and duration of the human immune response to Covid-19 until people who have recovered have been studied for months.
Paul Hunter, a communicable diseases specialist at the University of East Anglia, said: “I will go out on a limb and suggest that the immunity will not last for a lifetime but will last for more than a few months — possibly two or three years.”
However, illustrating the range of medical opinion, Martin Hibberd, professor of emerging infectious disease at the London School of Hygiene & Tropical Medicine, was more optimistic.
“The evidence is increasingly convincing that infection with [Covid-19] leads to an antibody response that is protective,” he said. “Most likely this protection is for life, although we need more evidence to be sure of this. People who have recovered are unlikely to be infected again.”
Seasonal factors will also help the government’s strategy of flattening and delaying the peak of the epidemic until the weather is warmer. Flu and other respiratory viruses are less prevalent in summer and many experts believe Covid-19 will behave in a similar way.
Mr Johnson and his pro-Brexit allies were prickly about the advice of “experts” during the 2016 EU referendum. Now the prime minister is taking a big political risk by backing them to the hilt on coronavirus.
Additional reporting by Jim Pickard and Martin Sandbu
