How Europe, after a fumbling start, overtook the U.S. in vaccinations.

Fear and recrimination shook European capitals, while Washington brimmed with confidence. In early April, the European Union lagged far behind the United States in Covid-19 vaccination, the gap was widening rapidly, and the World Health Organization berated Europe for an “unacceptably slow” pace.

But the U.S. effort peaked that month and then nose-dived, while the E.U. campaigns, so recently a target of ridicule, grew faster than those in any other region of the world. This week, the European Union pulled ahead of the United States in total vaccinations, adjusted for population. In July, it has given shots at four times the American pace — a turnabout that would have been hard to imagine in the spring.

Early on, while the United States and a handful of others surged ahead, the Europeans undermined their inoculation campaigns with repeated stumbles, delaying vaccine purchases, damaging public confidence in some shots and bungling the rollout when doses became available.

Now, the European Union is on a pace to end this week having given about 105 doses per 100 people, and at least one to just over 70 percent of adults, while the United States is at about 103 per 100 people and 69 percent of adults.

“The catch-up process has been very successful,” Ursula von der Leyen, president of the European Commission, the E.U. executive branch, said this week.

But the reversal is not just a story of the European Union and its member countries working out the early kinks, and in fact their vaccination campaigns remain far from trouble-free. Major political differences between the United States and Europe set them on divergent paths.