China after zero-COVID

Published December 20, 2022

Key takeaways:

  • We project over 300,000 deaths in China in the coming months, and more than a million over the course of 2023.
  • Why? China has a large number of people who have never gotten COVID or been vaccinated against it, leaving them susceptible to severe illness or death if Omicron begins to spread.
  • How can China manage the spread of infection?
    • Eventually most people will get exposed or infected with Omicron, but the pace can be slowed to reduce burden on hospitals by increasing mask use and imposing moderate restrictions on gathering (not a complete lockdown).
    • The death toll can be reduced by scaling up access to antivirals and deploying more effective vaccines, like Moderna or Pfizer.

This transcript has been lightly edited for clarity

What are the contributing factors to increases in COVID around the world?

In this weeks forecasts of the COVID epidemic around the world from IHME, the critical issue is what's happening in China and how that will unfold. And in the rest of the world, there are increases in COVID in a number of countries. These are increases that we have expected to see due to winter seasonality in the Northern Hemisphere.

And its playing out sort of as expected and is not larger than perhaps what we had expected many weeks ago. But the situation in China is much more complicated. We have been saying for the better part of the last 10 months that we dont really know what will happen in China because the critical determinant is when the zero-COVID strategy would be abandoned.

What will happen when zero-COVID ends?

It does appear now that there is a great reduction in the controls around transmission in China. And our models suggest that there will be a very large epidemic in China as those restrictions come off.

Now, the critical thing to ask in the case of China is what is the combination of a population thats been vaccinated with a somewhat less effective vaccine, or quite a bit less effective vaccine than, for example, Moderna and Pfizer; low vaccine uptake, even of that relatively less effective vaccine, in the 80-plus population; and so far, as far as we understand, no access to antivirals on a broad-based basis.

The best model for that experience is what happened in Hong Kong with the BA.1 epidemic that occurred in Hong Kong, which led to 10,000 deaths in about a one-month period.

As we look in our models – factoring in that we think when things get very bad, some restrictions will go back in – we still see that there will be greater than 300,000 deaths in the coming months in China. And, in longer-range forecasts, we expect that number over the course of 2023 to reach above a million deaths.

Why will there be so many deaths?

Well, theres this huge number of susceptible individuals because of either low efficacy of the vaccine, the vaccine was delivered quite some time ago, and so immunity has waned, as well as those who have never been vaccinated. We also know from experience with COVID that the initial wave, even with Omicron, as seen in Hong Kong in an immunologically naive group, can have quite considerable mortality.

If you think about Hong Kong, 8 million people, 10,000 deaths, and during that period you had an infection-fatality rate that was about 0.1%. And if you apply that to the whole country of China, you get some very large numbers. And thats why we do expect that the death toll will be very considerable in China.

When will the death toll begin to rise?

Well, our models suggest that we will see the current decline bottom out and then start to go back up in January.

We expect a peak of transmission toward the end of March and then a slow decline from there with perhaps continued, as weve seen in Hong Kong, transmission throughout 2023.

What are the strategies available for China to manage this?

The numbers Ive been quoting reflect what we think will happen, which is, province by province, serial use of mandates to slow the transmission, perhaps reduce the burden on hospitals, but fundamentally not to change the long-term outcome because eventually most people will get exposed or infected with Omicron.

Its really a question of spreading out the harm from this Omicron wave that we see coming in China. Wider-spread, consistent mask use will lower the toll. A more aggressive implementation of mandates, as weve seen throughout 2022, could stop transmission. We just are not building into the models that there will be complete lockdown as in a zero-COVID strategy reimposed.

So grim prospects for China in the coming months. And there are strategies which have so far not been adopted, such as trying to deploy a more effective vaccine (Moderna or Pfizer) or trying to scale up access to antivirals, both of which could considerably reduce the toll in China that is expected in the coming months.