China’s covid data is bad. An epidemiologist says that is making the surge nearly impossible to track.

China’s zero-covid policies created a coronavirus tinderbox; it may have just ignited. But accurately tracking this conflagration of covid has become virtually impossible.

Now, as China’s government abandons covid control measures, the country with perhaps the largest population of immunologically susceptible people on the planet is facing a potentially catastrophic situation.

The Chinese government says that only about 5,200 have died of covid throughout the entire pandemic, with just about a dozen this month.

This interview has been edited for length and clarity.

Katelyn Jetelina: We really know very little. And that is because the government has stopped reporting cases, hospitalizations, deaths. I think that they have reported a handful of genomic surveillance sequences, but certainly not enough to be helpful right now. So we’re really dependent on our epidemiology 101 knowledge about how viruses spread and how much we know about SARS-CoV-2, as well as anecdotal reports on the ground. And there are plenty of those showing that that situation in China is very grim right now.

We also have anecdotal reports from physicians on the ground and things like videos inside of hospitals being leaked — which are really important, since we always need to pair up qualitative data with quantitative numbers to give us kind of a full contextual framework of what’s going on.

And third, we’re relying a lot on travel surveillance. Some countries that are testing on arrival from China are also doing genomic sequencing. Italy, for example, is reporting genomic surveillance of their travels, and with countries doing that, we have a pretty good understanding of what variant is circulating in China.

But I think it’s important to highlight that this is more of a possibility rather than a probability. And that’s because transmission is high everywhere; it’s jumping from person to person very quickly in the United States.

The other thing I think we need to keep in mind is that the variant that we think is currently causing the wave in China, which is BF.7, is a couple evolutionary steps behind what’s currently spreading in the United States and most of the world. A new variant could erupt from China, but that doesn’t necessarily mean it will be able to dominate in places where XBB, for example, is circulating — like the United States. There’s a lot of things that would kind of have to go wrong for the outbreak in China to have major variant implications for the globe. But it is a possibility.

The challenge with this, at least in the United States, is we don’t have a very robust and dynamic surveillance travel program. It’s kind of like finding a needle in the haystack. But I still think it’s worthwhile to ramp that up as much as possible.

I’m not optimistic about this policy, mostly because if we’re buying time, it’s really only useful if we actually did something with that time, and it’s not clear what that plan would be. What are we going to change in the next week or two with that bought time? Every policy like this is incredibly difficult, but to me, epidemiologically, it’s just not adding up.