We may be entering Covid’s least predictable year yet
China’s unleashing of the virus is raising questions about the potential for harmful, new variants
Anjana Ahuja
© Andy CarterThe Covid-19 outbreak is officially three years old on January 30, which marks the moment in 2020 when the World Health Organization declared the respiratory disease a public health emergency of international concern.
But this month’s anniversary offers little to celebrate in the wake of China’s chaotic and abrupt lurch from zero-Covid to full-Covid.
Beijing has dramatically reduced testing, junked contact tracing and is scrapping most quarantine requirements; some regions now permit infected people with mild or no symptoms to go to work.
The pandemic virus is thus free to circulate unobserved in a sixth of the world’s population — just as the rest of the globe is clamouring for normality.
As the third year of the outbreak closes amid reports of overflowing hospitals in China and fresh restrictions on air travellers, and with the Chinese new year holiday fast approaching, the pandemic seems somehow more familiar and less predictable than ever.
China is right to abandon its inhumane and unworkable zero-Covid policy, but it has done so from a position of relative weakness.
A headline 90 per cent vaccination rate masks the reality that its homegrown vaccines are less effective than the mRNA ones used widely elsewhere, and that around 30 per cent of the country’s 260mn over-60s (and more than half of its over-80s) have not received a third dose.
Those factors have led to hair-raising projections, ranging from 1mn deaths this year to 1.7mn deaths by the end of April — and has prompted the EU to offer free vaccines to China.
Tellingly, China recently altered the way it counts its Covid dead, including in its tally only those who expire directly from respiratory failure and pneumonia.
The official nationwide Covid death toll in December appeared to total an unfeasible 14.
While Chinese officials privately estimated nearly 37mn new infections on December 20, no new cases have been reported since December 23.
The situation feels surreally different from last year, which saw serious discussion over whether WHO should declare an end to the Covid emergency.
Leaving aside the domestic tragedy, one question for the rest of the world in 2023 is whether unrestrained transmission in China will give rise to a new variant that is able to sneak past the immunity conferred by existing vaccines.
Some variants can drive new waves of infection, as happened in late 2021 when Delta was usurped by Omicron.
That created Omicron surges around the world in 2022 and accelerated vaccine reformulation.
Data indicate that the two commonest strains currently circulating in China are Omicron subvariants descended from BA5, the strain that plagued the US and Europe last year.
Scientists, particularly those on WHO’s technical advisory group on Sars-Cov-2 evolution scheduled to meet yesterday, are now on the lookout for ‘pi’, Omicron’s potential successor.
What matters is whether any new viral incarnations are able to spread more easily or make people sicker (or both), meriting designation as a “variant of concern”.
Professor Eddie Holmes, the Sydney University evolutionary biologist who helped colleagues in China to share the genome of the original Wuhan strain in early 2020, speculated that the low Covid transmission to date in China offered less pressure for the virus to evolve, limiting the chances of a dangerous variant emerging in the region.
“My take is that Sars-Cov-2 in China has an open goal in front of it: a population with very low levels of standing immunity,” he told me in an email, suggesting that the dominant variants in the country would most likely be those that gained a foothold at the start of the outbreak.
“It’s not obvious to me that there will be strong immune selection for antigenically distinct variants because so little of the population [in China] has prior immunity.”
Populations with larger but waning immunity, Holmes wrote, were more likely to be sources of new variants, adding “it is notable that XBB 1.5 was first detected in the US”.
XBB 1.5, a subvariant of Omicron, is fast becoming the dominant strain in the US, now accounting for around four in 10 cases according to the US Centers for Disease Control and Prevention.
The good news, at least for now, is that XBB 1.5 is not causing an uptick in hospitalisations and deaths, despite being nicknamed the Kraken.
In other words, the vaccines are still working.
That is worth toasting, even if, with a precarious situation in China and a new variant in the mix, we cannot be sure that the pandemic’s third anniversary will be its last.
The writer is a science commentator
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