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How well will vaccines work?

Covid-19 may become endemic. Governments need to start thinking about how to cope

Even miracles have their limits. Vaccines against the coronavirus have arrived sooner and worked better than many people dared hope. Without them, the pandemic threatened to take more than 150m lives. And yet, while the world rolls up a sleeve, it has become clear that expecting vaccines to see off covid-19 is mistaken. Instead the disease will circulate for years, and seems likely to become endemic. When covid-19 first struck, governments were caught by surprise. Now they need to think ahead.

To call vaccination a miracle is no exaggeration. A little more than a year after the virus was first recognised, medics have already administered 148m doses. In Israel, the world’s champion inoculator, hospital admissions among those aged below 60, who have not received a jab, are higher than ever. By contrast, among the largely inoculated over-60s they are already nearly 40% below their mid-January peak and they will fall further. Although vaccines fail to prevent all mild and asymptomatic cases of covid-19, they mostly seem to spare patients from death and the severest infections that require hospital admission, which is what really matters. Early evidence suggests that some vaccines stop the virus spreading, too. This would greatly slow the pandemic and thus make it easier to alleviate lockdowns without causing a surge of cases that overwhelms intensive-care units. Those findings, and many more, will harden up over the next few months as more data emerge (see article).

However, despite all this good news, the coronavirus is not finished with humanity yet. Covid-19 will continue to circulate widely. There is a growing realisation that the virus is likely to find a permanent home in humans, as “The Jab”, our new podcast, which launches on February 15th, will explore. That has profound implications for how governments need to respond.

One reason the coronavirus will persist is that making and distributing enough vaccine to protect the world’s 7.8bn people is a Herculean task (see article). Even Britain, which is vaccinating the population at a faster rate than any other big country, will not finish with the over-50s until May. To add to the burden, the potency of a jab may fade, making boosters necessary. Outside the rich world, 85% of countries have yet to start their vaccination programmes. Until the billions of people who live in them have felt the prick of a needle, which may not be before 2023, they will remain fuel for the virus.

Another reason for covid-19’s persistence is that, even as vaccines are making sarscov-2 less infectious and protecting people against death, new viral variants are undoing some of their good work. For one thing, successful variants are more infectious—anything from 25-40% in the case of b.1.1.7 which was first found in Britain. Infection is governed by the dizzying mathematics of exponential growth, so cases and deaths accumulate rapidly even if the variant is no more deadly. To get a given level of viral suppression, more onerous social distancing is needed.

In addition, new variants may withstand current vaccines. The ones found in Brazil and South Africa may also be defeating the immunity acquired from a previous covid-19 infection. The hope is that such cases will be milder, because the immune system has been primed by the first encounter with the disease. Even if that is true, the virus will continue to circulate, finding unprotected people and—because that is what viruses do—evolving new strains, some of which will be better at evading the defences that societies have mounted against them.

And the third reason sarscov-2 will persist is that lots of people will choose to remain a target by refusing vaccination. A total of 10m Britons are vulnerable to the disease, because of their age or underlying conditions. Modelling suggests that if just 10% of them declined to be vaccinated and if social distancing were abandoned while the virus was still liable to circulate at high levels, then a tremendous spike in infections and deaths would result.



In reality, the share of the overall population that remains unvaccinated is likely to be much higher than in that thought-experiment (see article). Vaccines are not yet licensed for children. Minority communities in many countries, which are most vulnerable to infection, tend to have less trust in the government and the medical establishment. Even among some care workers, as many as half refuse vaccination, despite having seen the ravages of covid-19 at first hand. With the new variants, about 80% of the overall population needs to be immune for an infected person, on average, to pass on the disease to less than one contact, the threshold at which the epidemic subsides. That will be a tall order.

For all these reasons, governments need to start planning for covid-19 as an endemic disease. Today they treat it as an emergency that will pass. To see how those ways of thinking differ, consider New Zealand, which has sought to be covid-free by bolting its doors against the world. In this way it has kept registered deaths down to just 25, but such a draconian policy makes no sense as a permanent defence: New Zealand is not North Korea. As vulnerable Kiwis are vaccinated, their country will come under growing pressure to open its borders—and hence to start to tolerate endemic covid-19 infections and deaths.

Across the world governments will have to work out when and how to switch from emergency measures to policies that are economically and socially sustainable indefinitely. The transition will be politically hard in places that have invested a lot in being covid-free. Nowhere more so than China, where vaccination is slow. The Communist Party has defined every case of covid-19 as unacceptable and wide circulation of the disease as a sign of the decadence of Western democracies.

The new coronormal

The adjustment to living with covid-19 begins with medical science. Work has already started on tweaking vaccines to confer protection against variants. That should go along with more surveillance of mutations that are spreading and accelerated regulatory approval for booster shots. Meanwhile treatments will be required to save more of those who contract the disease from death or serious illness. The best outcome would be for a combination of acquired immunity, regular booster jabs of tweaked vaccines and a menu of therapies to ensure that covid-19 need rarely be life-threatening. But that outcome is not guaranteed.

To the extent that medicine alone cannot prevent lethal outbreaks of covid-19, the burden will also fall on behaviour, just as it has in most of the pandemic. But rather than national lockdowns and months-long school closures, which come at a huge price, the responsibility should fall more heavily on individuals. Habits like mask-wearing may become part of everyday life. Vaccine passports and restrictions in crowded spaces could become mandatory. Vulnerable people will have to maintain great vigilance. Those who refuse vaccination can expect health-education and encouragement, but limited protection. As our special report on the travel industry makes clear, people’s desire to live their lives will ultimately be hard to resist, even in autocracies like China that may be reluctant to leave zero-tolerance behind.

The persistence of acute infections and chronic, debilitating “long covid” means that the next stage of the pandemic sounds grim. But even if covid-19 has not been completely put to rest, the situation is immeasurably better than what might have been. The credit for that goes to medical science.




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