1 December 2021

The global race to contain Omicron

As countries close their borders over fears of the new variant, we are reminded that the pandemic is far from over.

What does Omicron conjure in your mind? I’ve seen the new “scariant” compared to Frankenstein’s monster and a Transformer, but I picture it as an overgrown mafioso named “Tiny”, whose trousers stop short of his feet, who uncomplainingly takes on all the dirty work and whose mother loves him. As well she might. The latest variant of the coronavirus that causes Covid-19 has already been reported in 17 countries, and the first sample to have tested positive for it, in South Africa, was only taken on 9 November – though it is possible it was circulating beneath the radar before then. That’s a lot of grandchildren in a short space of time.

We’ve had effective vaccines against Covid-19 for about a year. Ever since then, some scientists have predicted that the unequal global distribution of vaccinations could force the virus to mutate in ways that would allow it to escape the vaccines’ ability to neutralise it. We don’t know if that has happened with Omicron, but more than 80 per cent of the world’s vaccine stock has gone to G20 countries. Meanwhile, the poorest nations – most of them in Africa – have received only 0.6 per cent. Where there is lower vaccine coverage, there is higher disease spread, which gives the virus more scope to mutate.

“This is precisely the reason why there has been such emphasis on vaccine equity,” said Beate Kampmann, the director of the Vaccine Centre at the London School of Hygiene & Tropical Medicine. “And that is coming back to bite us now.” Along comes Omicron, wiping all other world events off the front page of newspapers and reminding us that the pandemic still has considerable firepower left in it. We’ve worked our way through just over half the letters in the Greek alphabet; how many more will we need?

Some of the previous scariants have proven underwhelming. Beta, which was also first detected in South Africa, in October 2020, was quickly ousted from the viral population by the fitter Delta variant. “Fitter” in this sense refers to evolutionary fitness – how well the virus is adapted to its host – and it’s the key determinant of viral success. A virus that is highly contagious but causes severe disease may not get a foothold, in part because humans will be more motivated to stop it. But viruses can boost their fitness in different ways – by increasing their capacity to replicate, say, or becoming resistant to drugs. Fitness is the sum of all these things, and we don’t yet know how Omicron’s fitness compares to Delta’s.

The World Health Organisation (WHO) says that it is too early to know how transmissible Omicron is, how severe a disease it causes, and to what extent it might escape existing vaccines. It is right to reserve judgement. The first cases were reported in students in Pretoria but transmissibility of the disease among students – who tend to be young and to cluster in indoor spaces – may not be representative. It also takes time for infection to become severe disease. “It will take us at least two weeks to figure out if [Omicron] will cause changes in the type of patient that we see admitted to hospitals,” says Kampmann. Lab studies are looking at how the variant behaves in cultured cells.

But the WHO is worried, and it’s not alone. Omicron carries an unusually high number of mutations, including 30 in the spike protein – the surface structure that allows it to force entry into a host cell. Public health officials are guided by the precautionary principle, and despite all the uncertainty around Omicron, the WHO classifies the risk it poses as “very high”.

There is some good news. Despite its genetic divergence, PCR and lateral flow tests have detected Omicron. There is no certainty that mass testing systems will pick up on new variants. It is possible that a variant could arise which the world only discovers when intensive care units become overwhelmed with sick people testing negative.

The fear is that some of Omicron’s mutations have altered those elements of the virus that the vaccine-generated antibodies bind to, which could result in the vaccines no longer preventing infection. The hope is that the T cell response will remain intact. That is, immune cells called cytotoxic T cells will still be able to kill other host cells that have been infected. They represent the second line of defence, meaning they can’t stop infection but they can reduce the chances of the disease being severe.

Neither the hope nor the fear have been substantiated yet, but companies including BioNTech and AstraZeneca are already working to adapt their vaccines to Omicron. If the T cell response does turn out to be undiminished, then a single booster of the variant-adapted vaccine could be sufficient to restore protection. It might take a couple of months to produce the updated vaccines, but the approval process should be relatively quick and straightforward – similar to that for the annually updated flu vaccine.

For now, we have to fall back on our age-old defences against contagion – everything that comes under the umbrella of physical distancing. Unfortunately for libertarians, it’s no defence to close the borders and whip off your masks. South Africa’s thanks for raising the alarm about Omicron was to find itself penalised by travel bans, none of which stopped the variant from reaching Europe or Asia. As Tedros Adhanom Ghebreyesus, the director-general of the WHO, said on 29 November, “Our current system disincentivises countries from alerting others to threats that will inevitably land on their shores.”

The virus is a bit like the mafia, in other words. It preys on individual and collective weaknesses. If you want to root it out, it’s no good blaming someone else. Better to look to yourself, and the gangster grinning over your shoulder, and ask what is the secret of their phenomenal success.