As the new strain spreads internationally, more nations are moving to secure third doses for their populations in hopes of staving off another wave of infections

(Originally published Sept. 3 in “What in the World“) Further evidence of the obvious benefits of vaccines against Covid: while you still may get infected, not only a vaccine reduce the likelihood of being hospitalized and dying from the virus, it reduces the chances of getting “long Covid.”

And with more health authorities realizing that current vaccines seem to provide waning protection against the delta strain, more are recommending vaccinated citizens get a booster shot. The Czech Republic is the latest, joining Israel, Germany, France and the United States. The move in Prague is interesting in that it seems to be largely preventive, as the Czech Republic appears to have so far avoided the global delta surge. But evidence from Israel, the first nation to begin offering booster shots, suggests a booster shot further reduces the risk of infection and, if infected, of severe disease.

The shift towards boosters has drawn criticism from the World Health Organization, among others including the European Center for Disease Prevention and Control, which argues that it diverts supplies of first doses from poorer countries where vaccination rates are still dangerously low. But accusations of vaccine nationalism appear to fall on deaf ears amid a pandemic, and the U.S. has just announced that it will invest $3 billion in companies that are part of the nation’s vaccine supply chain. It’s unclear how that might help the makers of the vaccines. Pfizer’s own supply chain is remarkably labyrinthine, however.

All of this is taking place as evidence grows that the latest Mu strain, first identified in Colombia, is spreading further. Japan on Thursday said it picked up some Mu infections in June and July (“oops, did we forget to mention that before the Olympics?”). It’s not yet clear whether Mu is more dangerous or more infectious than Delta, or how effective vaccines are against it. The WHO still classifies Mu as a “variant of interest.” It will have to work hard to merit the WHO’s “variant of concern” label. And two new challenger strains have been identified, one in South Africa and another in Turkey. New mutations pop up all the time, however, so it’s important not to get too worked up about any particular one until it demonstrates that it can displace its forbears in terms of impact. What we have to hope is that one of these new strains is more infectious than Delta, but is content not to cause severe disease or kill its hosts.