After a bumbling start, Europe has surpassed the U.S. in its COVID vaccine drive, just over six months into an international effort to vaccinate the world out of the coronavirus pandemic.

In the past week, Italy, Germany, and Spain have all overtaken the U.S. in terms of the percentage of the population that has received at least one shot against COVID-19, with France running close behind. As of June 29, Italy, Spain, and Germany have rates between 56% and 54.1%, while the U.S. stood at 53.8%. (The U.K., with a rate of 65.9%, is well ahead of them all.)

Few would have predicted this turn of events at the start of the year, when the world’s vaccine campaigns began taking off, and the U.S. resource advantage seemed insurmountable.

Europe’s vaccine rollout was disastrous. Supply shortfalls prompted a vicious blame game over who was responsible for negotiating what were seen as flawed vaccine contracts, and in response EU leaders engaged in an ill-advised effort to shift citizen ire to the U.K. and vaccine maker AstraZeneca and cut jab exports from the bloc. The slow start also sank the eurozone economy as member states adopted strict lockdown measures to curb contagion.

Since then, however, European governments have organized aggressive vaccination campaigns, engaged in intense pro-vaccine messaging, and, most important, received a flood of supply from vaccine makers.

Operation Overtake

Europe has also been aided by leaders who have promoted vaccine use, and a public that is generally less skeptical of medical science.

With the exception of France, vaccine willingness in major European economies is higher than that in the U.S., where high vaccine hesitancy has slowed the push, leading the U.S. vaccination rate to plateau at around 54% of the population.

The latest figures from Our World in Data, which collects national COVID data on a daily basis, shows how quickly Europe has caught up and overtaken America’s vaunted “Operation Warp Speed.”

In the final week of June, the number of people who said they had or would take the vaccine ranged from 81% in Germany to 85% in Italy to 90% in Spain, with the U.S. and France trailing, posting rates of 80% and 74%, respectively, according to survey data supplied to Fortune by Ipsos. (A separate survey, from YouGov, meanwhile, showed an even starker vaccine acceptance divide between the United States and the Spanish-German-Italian bloc.)

Still, Europe has a way to go in its vaccination efforts.

In the U.S., some 46% of people have fully completed their (mostly) two-dose vaccine regimens, while in major European countries the rates range from 31% to 37%.

That has major implications for handling the Delta variant of the coronavirus, which is on track to become the dominant strain. Early studies show both doses of the two-jab vaccines, such as those from BioNTech/Pfizer and Oxford/AstraZeneca, are needed to provide sufficient protection against Delta. For good measure, German health authorities say that full coverage of 80% of the population will be needed to provide “basic protection” against this particular strain, which was first identified in India.

Meanwhile, here is how Europe’s biggest economies caught up to the United States.

Italy

In March, Italy’s newly installed Prime Minister Mario Draghi appointed an army general, Francesco Paolo Figliuolo, to run the country’s vaccination drive. He brought military precision to a floundering campaign, and once supplies picked up in May, the campaign went into overdrive.

Italy is currently on pace to vaccinate a bit more than 10% of the country every three weeks, which should put it in line to hit Figliuolo’s vow, made in March to much skepticism, of fully vaccinating 80% of Italians by the end of September.

When Figliuolo took over, there were more than 30,000 Italians in the hospital with COVID, with 3,800 in intensive care. Those numbers have fallen by 90% since, Italy’s health minister, Roberto Speranza, triumphantly declared last week.

For most Italians, the public health care system is still a source of national pride. That may go some way to explaining the most recent polling data showing relatively high vaccine acceptance rates for the COVID jab. Now that the supply bottleneck of jabs is sorted out, pent-up demand is expected to help the country achieve its goal of getting all adult Italians at least one jab this summer.

Germany

Germany’s overtaking of the U.S. on initial doses earlier this week came as vindication of health minister Jens Spahn’s decision to remove prioritization limits on vaccinations for adults in early June. Some states, including Berlin and Bavaria, had made similar moves not long before, drawing criticism from Susanne Johna, head of the German Doctors’ Association, who complained that “even more people are now competing for a scarce commodity.”

As it turned out, the commodity quickly became less scarce—in part thanks to the slowdown in the U.S. vaccination drive. In short, American vaccine hesitancy means unused doses need to go somewhere before they expire, and some European countries have been quick to snap them up.

Along with Denmark and Croatia, Germany has been a major beneficiary of Moderna vaccines coming in from the U.S. at higher rates than previously foreseen. Germany was expecting to receive 733,000 Moderna doses per week this month, but on the weekend Spahn said the July intake would reach a whopping 1.33 million per week. Under current forecasts, nearly 3 million Moderna doses will be arriving per week in September.

Supply will soon outstrip demand, Spahn said Saturday, noting that hundreds of thousands of Oxford/AstraZeneca and Johnson & Johnson doses—seen by many Germans as inferior to Moderna and BioNTech/Pfizer’s mRNA-based vaccines—are already sitting unused in medical practices.

The minister said German health workers will soon be able to start offering shots to passersby in city centers and at places of worship, as the country races to hit the 80% target and beat the Delta variant. Indeed, Germany will be swimming in so many doses that it aims to sell on 30 million in the second half of the year.

Spain

Spain’s vaccine turnaround began in early April, when Prime Minister Pedro Sánchez, under fire for Spain’s slow rollout and devastated economy, announced the beginning of the “largest vaccination campaign in the history of Spain.”

During the first three months of 2021, Spain had been supplied with 9.7 million vaccine doses and only 5.5 million Spaniards—or 11.7% of the population—had received at least one dose. In his April speech, Sánchez said deliveries in the second quarter would jump to 38 million doses, and set out a series of vaccination milestones.

Faced with a flood of vaccines, Spain’s regional health departments set up aggressive vaccination programs. In Barcelona, the Catalan government repurposed the Fira convention center and the Camp Nou stadium of FC Barcelona for mass vaccinations, while Madrid opened mass vaccination centers in the downtown WiZink concert hall and the Atlético de Madrid soccer stadium.

Last week, Madrid—a region known for its active nightlife and relatively early loosening of COVID restrictions—went further, opening a 24-hour mass vaccination center in an area hospital, which administered 827 doses the first night. And in the southern region of Andalucía, the regional government added another incentive, announcing that it would offer doses to tourists staying for more than a month.

While Spain fell some 570,000 short of its mid-June goal of 15 million fully immunized people, and by June 29 had only received 35.5 million of the 38 million doses expected in the second quarter, the aggressive vaccine rollout, aided by a low level of vaccine hesitancy—91% of Spaniards said they had received or would receive a vaccine, according to YouGov—had gotten 53.4% of the population, or 25.3 million, vaccinated with at least one dose.

“Vaccination in Spain has advanced well, according to an ambitious plan,” said Rafael Bengoa, a former WHO director and health minister of the Basque region, adding that Spain should have 70% of its adult population fully vaccinated by September.

Bengoa counseled caution, however, noting that infection rates are rising again after superspreader events among unvaccinated youth, such as massive end-of-school parties in Mallorca that left more than 1,200 people infected.

France

Facing widespread vaccine hesitancy among the French—and, like much of the European Union, a dire shortage of COVID-19 vaccines—President Emmanuel Macron chose such a cautious approach that the program virtually stalled on takeoff around Christmas last year.

Only the country’s 60,000 or so physicians were authorized to vaccinate people. And each jab required a consultation with a doctor about the possible risks, and after that, a signed consent form. “We are in Kafka territory here,” French economist Antoine Lévy told Fortune at the time.

Macron finally jettisoned his go-slow strategy after the second coronavirus wave sent new cases soaring in the spring, to more than 35,000 a day. He deployed firefighters to vaccinate people at their stations and turned the country’s national football stadium in Paris, which seats 81,000 people, into a mass vaccination site capable of jabbing thousands of people a day.

And on June 29 health officials erected a pop-up vaccination marquee in Paris’s huge Place de la République, specifically to vaccinate food-delivery gig workers, whose working hours made it difficult to get to vaccination sites. For many delivery workers, being able to cycle by for a vaccine without even locking up their bikes was too convenient an offer to pass up. “Since this is without an appointment, and I don’t work far from République, I came,” Guillaume Girard, who delivers for Uber Eats, told Le Figaro.

France is now vaccinating more than three times the percentage of people as the U.S., up to about 8.6 per 100 people over the past week, compared with the U.S. rate of about 2.5.