As Covid evolves, trade-offs must be reassessed

The British and South African variants will spread quickly, creating deep difficulties for policymakers.

People queue at an NHS Covid-19 vaccination centre for the Pfizer-BioNTech vaccine in London. Picture: AFP

The northern winter solstice may have passed, but in the land of COVID-19 the nights are still growing longer. In recent weeks two variants of the coronavirus have spread with ferocious speed in Britain and South Africa. They have mutations that make them a lot more contagious. Although so far they do not seem to be any deadlier, for every 10 people that older variants would infect in Britain the new one infects 15. Early data suggest the South African variant burns just as fiercely.

Just now the world is rightly focused on approving, making and administering vaccines. Alas, it also needs to face up to the fact that before jabs come to the rescue, the new variants will spread, creating deep difficulties for policymakers.

Evolutionary biologists have shrugged at the appearance of the mutations: this is how viruses behave, for natural selection favours variants that are more transmissible and less deadly. Some viruses that cause common colds may have started out as vicious as SARS-CoV-2 and moderated in their old age. Policymakers cannot afford to be so relaxed. A more transmissible COVID-19 virus that is just as dangerous as this variant is means that hospitals may be overwhelmed. In England most of the population has been in near-full lockdown for weeks. Yet COVID-19 patients at hospitals now have exceeded the peak in April and the health service is struggling to cope.

Much of the rest of the world, including Europe and the US, will soon follow. More than 50 countries rushed to ban travellers from Britain as soon as its scientists told the world about the new variant in mid-December. Many also have banned arrivals from South Africa.

But such measures are likely to buy only a little time. In early November, before travel bans, the British variant already accounted for almost 30 per cent of cases in London, one of the world’s most connected cities.

Given how early variants spread from ski resorts in the Alps last northern winter and from Spain in the summer, it is naive to believe that cases are not already seeded all over Europe and beyond. Once it arrives, the new British variant is likely to displace local strains within a few weeks.

So far, only sporadic cases of it have been found in 20 or so countries, including in the US in a man who had not travelled. But that is because, unlike Britain and South Africa, most do little genomic sequencing to look for mutations. Other more contagious variants may thus be spreading undetected.

At least five cases of the British variant have been detected in Australia, two in NSW, two in Victoria and one in South Australia, with all cases in hotel quarantine. This week Australia detected its first case of the South African variant when a woman in Queensland hotel quarantine tested positive for the new COVID-19 strain.

The good news is that these mutations are unlikely to reinfect people who have had the disease or to evade today’s COVID-19 vaccines. Natural selection eventually will begin to change that as more and more people are inoculated, but vaccines can be tweaked to remain effective. With the Pfizer-BioNTech vaccine, the process takes only six weeks.

However, even in the mostly rich countries that have hoarded vaccine supplies there will not be enough to stop the virus from spreading. This week’s emergency approval of the AstraZeneca-Oxford jab will help, but there still will be delays. Poorer and middle-income countries will remain less well protected for a lot longer.

Countries will be forced to deal with this fast-changing reality by reassessing the trade-offs between the benefits from the harsh lockdowns needed to stop a more contagious virus and their long-term costs to schooling, health and livelihoods.

There is still light at the end of the tunnel. But the road through it has become a lot more treacherous.