Omicron, by far the most contagious coronavirus variant to date, is so rampant around the world that it is easy to feel despondent about the prospects of the pandemic easing — let alone coming to an end — in 2022. But there are good reasons to think that Covid-19’s toll on global health and its wider social and economic impact could wane this year, if governments and health authorities follow appropriate policies and if this volatile virus develops in the way that many scientists believe is most likely.

A debate is growing between those who think new pathogens such as Sars-Cov-2 tend to cause milder disease as time passes and those who say they are just as likely to evolve in a more virulent direction. Without taking sides, it is reasonable to conclude that the interaction between virus and the human immune system means that the more people acquire some protection against severe Covid-19 symptoms through vaccination or infection, the better the outlook. No conceivable descendant of Sars-Cov-2 could have enough mutations in the right places to escape fully the attentions of both antibodies and T-cells generated by prior exposure to an earlier variant.

The top priority is, therefore, to vaccinate the whole world — as it should have been for the past year. Unfortunately, Covid-19 vaccine inequity has never been greater, with just 10 per cent of the population in low-income countries having received at least one jab, according to the World Health Organization, while wealthy nations are rolling out third or even fourth shots. As the WHO says, with global vaccine production close to 1.5bn doses a month, there will be enough for these booster programmes to continue, while directing far more supplies to poorer countries than in 2021, through schemes such as Covax.