The Economist: What to do about covid-19’s threatening new variant
South Africa’s scientists have bought the world time on Omicron. It should use it
BACK IN 2019 it took a month for the warning to go up about a new respiratory disease in Wuhan; and another month for America to suspend flights from China. By then large amounts of the coronavirus had spread around the world. By contrast, the recent identification of a new and potentially dangerous variant of covid-19 in South Africa took place within days. Travel bans followed within hours. Indeed some were announced even before the World Health Organisation had dubbed the new variant Omicron (they tactfully missed out the Greek letter Xi, which might have caused offence in China).
The admirable work of South Africa’s scientists and their exemplary openness, along with the rapid recognition that Omicron poses a genuine threat, show that the world has learnt a lot about dealing with pandemics in the past two years. However, the very fact that Omicron was spotted early, using sparse data, means that its true nature will remain unclear without further research. The real test of pandemic preparedness will be how wisely the world uses the time it has won.
One task is to answer some pressing questions. The most important is whether Omicron will displace the Delta variant, which is causing 2.5m cases a week in Europe alone. Early evidence in South Africa suggests it spreads very fast indeed. The possibility that it was already dispersed there may explain why sporadic cases are turning up all over the world, including 13 in the Netherlands, three in Britain, two in Denmark and Australia and more, along with over 1,000 suspected infections.
But there are complicating factors. The level of immunisation in South Africa is fairly low and recorded cases there were until recently about 1% of their peak in July. Perhaps that gave Omicron a head start, turbocharged by a series of super-spreading events. Other variants, including Gamma and Lambda, looked dangerous for a while before they faded. Yonatan Grad, professor of immunology and infectious diseases at Harvard, has tweeted that transmissibility could take two to four weeks to work out.
Another question is whether Omicron causes severe disease. Early reports of mild cases in South Africa are not conclusive. They may have described symptoms in mostly young people, who are less vulnerable to all variants of covid-19.
To establish a comparison with other variants, scientists need to observe enough cases across a range of ages and in people with secondary conditions, such as chronic kidney disease and diabetes, that are known to make catching covid more dangerous. One thing to remember is that, if Omicron turns out to be less virulent than Delta but much more infectious it could still lead to a rise in hospital admissions and deaths. Dr Grad reckons that assessing Omicron’s severity could take one to two months.
A third question is how much protection vaccines, prior infections and medicines give against Omicron. The grounds for concern are mostly theoretical. Omicron has roughly 30 mutations on the spike protein, some of which are thought to help virus particles enter human cells and others of which frustrate attacks from antibodies. There are around 20 more mutations elsewhere in the viral genome: some of them may also be dangerous.
There is anecdotal evidence of fully vaccinated people catching the disease, but this is hardly surprising as that is a trick which Delta already pulls off. What matters is how common such cases are, how easily they pass on the disease and, crucially, what share of them end up in intensive care and an early grave. Dr Grad thinks data on vaccines will be available within one to two weeks.
Perhaps Omicron will never amount to much. Even so, governments can use the time they have to prepare in case it does. Early travel bans and quarantines will slow its spread out of South Africa by lowering the number of individual outbreaks seeded by new arrivals. That in turn helps track-and-trace systems keep up.
However Omicron may soon prove so infectious that track-and-trace is swamped. If so, transmission from within communities will rapidly become more important than cases spread by the occasional international traveller. At that point, travel bans should immediately be lifted—after all, South Africa is currently being punished for its good citizenship.
A second task is for pharma companies to be able to make new vaccines. These target the spike protein and Omicron’s is heavily mutated. The mRNA vaccines, in particular, can be rapidly edited with the new variant’s genome, tested and then manufactured at scale. They say that will take 100 days or so. The other vaccines, where scaling is harder, could take longer. Work has already begun.
Whether administering these new vaccines actually makes sense remains to be seen. Jeremy Farrar, head of the Wellcome Trust, a medical charity, points out that the ideal jab is optimised to guard against a range of existing variants. Specialising in an exotic one like Omicron may not be the best strategy.
Meanwhile governments can accelerate booster programmes on the reasonable assumption that today’s vaccines confer at least some protection against the new threat. Such third shots make sense whether Omicron comes to dominate or not. That is because their primary task is to protect against Delta, which is currently sweeping through Europe and once again threatens the United States.
If Omicron starts to spread, governments will have to fall back on non-pharmaceutical interventions. The least disruptive are mask-wearing, reasserting the two-metre rule, working from home where possible and improved ventilation. If Omicron really is much more infectious than Delta, then the efforts required to stop it spreading will have to be correspondingly more strenuous. Lockdowns of increasing scope are, as ever, a last resort to be reserved for when cases look as if they are about to overwhelm the health system.
For all of this to work, governments need to know when to act. And that depends on understanding how the new variant is spreading. By a stroke of luck, a common PCR test fails to detect one of its target genes when analysing Omicron, because the virus’s genome has a mutation. PCR tests are faster and cheaper than a full sequencing of the virus. They can therefore serve as a useful rough guide to Omicron’s status (though they are hardly failsafe, as some other variants also behave this way).
Governments have got things wrong at every stage of the pandemic. But their most consistent mistake has been to act too late, when cases are already out of control. With Omicron, South Africa has bought them time. How well will they cope?