Concerns over unsustainable omikron epidemic in China

Since the beginning of the pandemic, China has been committed to a “zero-covid policy”: whenever the virus raises its head somewhere, it immediately intervenes so as to extinguish the epidemic. But that policy no longer seems sustainable: the Chinese population no longer accepts the rigorous measures. And now the omikron variant, far more contagious than any previous variant, affects a population of 1.4 billion people with low immunity. Scientists fear a boom in hospitalizations and deaths, and an explosion of new subvariants.

1 How is the pandemic in China?

China reported 159,000 new confirmed corona cases per week on Nov. 14. That number is dwindling after a peak of 334,000 on Oct. 3 as China is trying to contain the new wave with lockdowns, tests and quarantines. The previous wave peaked at the end of May with 576,000 cases a week.

Thanks to its strict zero-covid policy, China has so far had far fewer coronavirus cases and deaths than many other countries: with strict lockdowns, quarantines and mass testing, the country has kept the virus under control. “The difficult thing now is to turn this zero-covid policy into a viable solution for Chinese society,” says Marion Koopmans, a virologist at Erasmus MC. “The only thing to do is let the infection spread with as little impact as possible. But it’s complicated.”

Some things have been relaxed: China has now reduced the duration of the quarantine to three days, but is still acting firmly if there are people who have tested positive. “With such a short quarantine you lose sight of the virus. The question is whether they still have it under control,” says Koopmans. “There doesn’t seem to be a clear exit strategy. This is worrying.

2 What variants are there?

Little is known about which subvariants are circulating in China, Koopmans says, even the WHO is in the dark. Omikron is the dominant coronavirus variant worldwide, but from that a swarm of dozens of subvariants has now emergedeach better evading defenses differently and moving more and more easily.

In Europe and the USA, for example, the subvariant BQ.1 is now taking the place of BA.5. A derivative of this, BQ1.1, evades all available antibodies that we have drugged patients. Fortunately, for the first time in the pandemic, this variant has not led to a new big wave in the West so far. All the infections, vaccinations, boosters and repeated vaccinations make it increasingly difficult for the virus to find a new host. But that immunity wall has no effect on Omikron in China.

3 What about vaccination coverage?

In China, 92% of the population received at least one dose of the vaccine, 90% received two, according to the Associated Press news agency. Enthusiasm for a vaccination was much lower among the elderly, at around 65%. There was also little interest in a third injection, a booster, because the virus was barely circulating.

It is not known exactly which vaccines have been used in China; in any case CoronaVac, a vaccine with inactivated virus produced by the Chinese company Sinovac. Vaccines against the original Wuhan virus variant, such as this vaccine, protect much less well against disease and death from omikron. Also, the shots were released over a year ago. All of this means that the Chinese population has little immunity against the virus.

4 What if Omikron breaks out in China?

If the virus circulates freely in a population of 1.4 billion people with little defense, millions will first be infected, possibly many thousands will die, and the pressure on health care will be enormous.

This also applies to an omikron infection, which multiplies less well in the lungs and thus produces a slightly milder clinical picture than, for example, the delta variant. In Hong Kong, which also had a zero-covid policy, a wave of infection swept the country in March, an emergency hospital was quickly erected. Omikron entered there via imported infected hamsters. This resulted in a large wave of infections with many hospital admissions, where thousands of residents died of Covid-19.

Virologists are most concerned about another consequence of an unsustainable epidemic in China. The faster a virus circulates and the more people it infects, the more likely it is to mutate. There is a high risk that an outbreak involving more than a billion people will result in a number of new subvariants. It is impossible to predict how they will behave.

“If China still manages to stretch the measures and fully engages in a rapid vaccination campaign, things could go better than expected,” says Koopmans. “But we have to take into account that Pandora’s box has been opened in China. This has no consequences for the Netherlands at the moment, but it tells me that we really need to keep monitoring how the virus develops.”