People are Still Pushing ‘Zero Covid’

If there was ever a time that ‘Zero Covid’ – the goal of eliminating Covid altogether – made sense, it was when the virus first appeared in Wuhan. Had the Chinese authorities raised the alarm sooner, and scrambled to contain the virus, perhaps there never would have been a pandemic.

But there was one. Covid has now been with us for two full years (perhaps longer). Hundreds of millions have been infected, and even greater numbers have received the vaccine. At this point, you might say, ‘Zero Covid’ is a non-starter.

Yet people are still pushing the idea. A recent article in the Daily Kos – a left-wing news site in the U.S. – argues that “COVID-19 must be eliminated, not become endemic, if America is to survive”.

Is this just a case where the headline is much more radical than the article itself? No – the one thing of which the author can’t be accused is attempting to downplay his position. “We cannot live with endemic COVID-19,” he writes, “Hang on, let me say that again: We. Cannot. Live. With. Endemic. COVID-19.”

Let’s consider his arguments, one by one. The author begins by comparing Covid to the flu, noting that the former is much more contagious. Whereas seasonal influenza has a basic reproduction number of 1.4, he notes, “COVID-19 has a R₀ that is over five. Maybe as high as 10.”

I don’t know where he got the figure of ‘10’ from, but even if you take the higher estimates of Covid’s R₀ at face value, they correspond to circumstances in which the population was immunologically naïve.

Once enough people have caught the virus at least once, the number still susceptible to infection will be substantially reduced. Not to zero, of course, as even natural immunity wanes – but enough to forestall the kind of transmission levels we saw in the spring of 2020.

Note: this is evident not just from the protective effect of natural immunity, but also from the declining transmission advantage of new variants. As immunity to each new variant rises (particularly among the subset of individuals who’re most likely to infect others), the effective reproductive number correspondingly declines.

The author then claims that a world with endemic Covid will be one where health care is much more expensive, due to demands placed on the system by constant surges of new Covid patients. Here again, however, he ignores the impact of natural and vaccine-induced immunity.

“Endemic COVID-19,” he writes, “would behave exactly the same as epidemic COVID-19: in surges, waves, or spikes.” Would it? What seems far more likely is that endemic Covid would not behave in this way. At the very least, any “surges, waves, or spikes” will be smaller and less deadly than those observed during the epidemic phase of the disease.

The author’s next argument is that, even once Covid becomes endemic, we’ll still see a lot of deaths. But as before, he fails to take account of immunity. “If the level of COVID-19 fatalities could be dropped to just 0.5%,” he writes, “then the rate of deaths would be “just” 160,000 people a year.”

Yet ‘0.5%’ is an implausibly high estimate of the IFR for a world where Covid is endemic. In a recent Twitter thread, Professor Francois Balloux used the figure of 0.1%, adding that even this was “probably far too pessimistic”.

The author then invokes the spectre of long Covid, noting that persistent symptoms “are not rare”. However, if he’d referred to the latest estimates from the ONS, he’d know that only 2–3% of patients still report symptoms after 12 weeks, and this is before you factor in widespread immunity.

Even if ‘Zero Covid’ were achievable, which it almost certainly is not, the costs of getting there would be enormous. We’d not only need a massive annual re-vaccination program, but also constant vigilance at the border, as well as large-scale testing in perpetuity.

“Whatever the price of defeating COVID-19 may be,” the Daily Kos article concludes, “it must be paid.” And that more or less sums up the case for, and against, ‘Zero Covid’. For you can’t take a proposal seriously if there’s no estimate of costs.