Vaccinated people with the Delta strain of Covid-19 are now passing the virus to the unvaccinated. The U.S. Army knows the solution: get the jab!

(Originally published Sept. 15 in “What in the World“) As the ranks of the vaccinated grow larger than those of the unvaccinated in the U.S. and other nations, the unvaccinated are casting off their social-distancing shackles and mingling maskless among the unvaccinated. Because a small percentage of vaccinated are still bound to catch the Delta strain without getting so much as a sniffle, this great mixing is only accelerating the frequency of breakthrough infections, and the vaccinated are increasingly giving the virus to the unvaccinated. That’s making the Delta surge fade less quickly than it might otherwise do.

This makes restricting public venues to the vaccinated a bit absurd: it’s the unvaccinated who are at risk from the vaccinated, not the other way around. Arguably, it should be establishments dedicated to the fallacy that vaccines are a government plot that ban the vaccinated to protect their preferred patrons, the vulnerable unvaxxed.

The real danger is that free-roaming vaccinated cook up a new batch of Covid that is even better than Delta at evading immunity. Until there are new, improved vaccines that specifically target Delta, however, the best course of defense is a) convince or compel the unvaccinated to get vaccinated and b) administer booster shots to the vaccinated to improve their immunity as it fades over time. The U.S. government has said that all its employees must be vaccinated by Nov. 22. The U.S. Army has decided it can afford to wait an additional seven months, and won’t compel troops to get fully vaccinated until June 30, 2022. So much for military preparedness.

How fast immunity fades is still a guessing game, but a group of scientists from the World Health Organization and some formerly from the U.S. Food and Drug Administration made headlines this week with a review in The Lancet arguing against booster shots.

The review is pure editorial wrapped in the guise of research, full of “mights” and “coulds” supported with footnotes and references—a blog in scientific jargon. It’s a compendium of quibbles with the few statistics we have supporting booster shots, including the latest evidence from Israel, which is doling out booster shots amid a massive surge in infections despite having inoculated more than 65% of its residents. The simple fact is that more Israelis are getting infected as their immunity fades.

The desperate aim of the Lancet writers is to convince rich countries to hold off on boosters and instead devote those doses to inoculating people in poorer countries who haven’t yet received a single dose. This blog has made the point that it makes more sense to get the 75% of the world with no shots vaccinated. But boosters may not be what’s holding that up. Even if we landed doses for every individual onto the tarmacs of every airport in the developing world, those countries still wouldn’t be able to deliver them to the arms of the needy recipients.

No onto some statistical navel-gazing. I’ve been eager to look more closely at how the Delta surge in Asia is differentiated. Asia’s surge is being led in these places:

Both Mongolia and the Maldives have some of the region’s highest inoculation rates, 63% and 58%, respectively. But most of Mongolia’s vaccinated got their jabs back in June, during the country’s previous wave of infections. And most people received vaccines made in China or Russia. As for the Maldives, it didn’t hit the 50% threshold until early August, after its own massive May surge had subsided. That suggests that Delta hit before it had managed to develop any herd immunity.

Mongolia has one of this group’s lowest stringency index scores. The Maldives has remained largely open.

Let’s compare that experience with those of the region’s less-affected nations. Here they are, with Vietnam and Japan thrown in for reference…

Only China and Singapore can arguably attribute their lower infection rates to high levels of vaccination. But in Singapore’s case, the low infection rate seems to be despite its high vaccination rate: that is to say that its latest surge has come almost immediately after it passed the 50% threshold. Like the Maldives, it got hit with Delta too soon for vaccines to protect it, which means that it was its remaining social-distancing measures kept the surge from getting worse. Its mistake was relaxing them to the extent it did too soon.

That’s why Asia’s more cautious approach to reopening is the more responsible path forward: it ensures that, once high vaccination rates are reached, authorities can still make sure breakthrough infections and infections of those remaining unvaccinated don’t take too high a toll, or that the relaxation of social distancing measures opens the door for the virus to mutate and evade herd immunity.

At the end of the day, though, every country is at the mercy of the most irresponsible, whose governments have largely given up on trying to minimize infections beyond doling out vaccines (hello, United States). As they reopen their borders, countries that have used restrictions on social activity still risk importing new strains that will undo all the sacrifices they’ve made.