New York magazine calls it “a disaster.”

Vanity Fair says it is “an absolute mess.”

A potential “shambles,” warns the U.K.’s Daily Mail.

That’s the prevailing take on the COVID-19 vaccine rollout so far in the U.S. and Britain. Less than two months after the first vaccine—Pfizer’s messenger RNA–based inoculation—received the first regulatory approval, more than 9 million doses of various COVID-19 vaccines have been administered in the U.S. and 2.45 million in the U.K. That’s enough to cover 2.8% and 4% of each country’s respective population.

Do these numbers really indicate a hopelessly bungled vaccination effort? And how does this compare with historical mass vaccination drives?

“What we’ve seen in the U.S. is an expectations game gone awry,” says Jason Schwartz, a professor of public health and the history of medicine at Yale University. “There were off the chart expectations from federal government about the pace of vaccinations.”

He said the current numbers were “absolutely not a disaster.” If they looked like one to some observers, he says, it is largely because the U.S. government foolishly predicted, in an attempt to bolster political support, that 20 million people would be vaccinated by the end of December 2020.

There are a few parallels for the current vaccination effort, which is aimed at inoculating almost the entire population and is taking place in the midst of a deadly pandemic. “This really is unprecedented,” says Paul Offit, a pediatrician and vaccine researcher at the Children’s Hospital of Philadelphia.

The closest historical analogy to the current challenge is the campaign to combat polio in the mid-1950s. As with COVID-19, the public had eagerly anticipated and tracked development of the first polio vaccine, developed by Jonas Salk with funding from a private charity—the National Foundation for Infantile Paralysis, better known as the March of Dimes, Schwartz says. The U.S. government approved wide-scale use of Salk’s vaccine in April 1955. By August, some 4 million doses had been administered, enough to have immunized about 10% of U.S. children under the age of 12, who were the main target population for the vaccine.

Cases of polio infection dropped dramatically within a year, from 14,647 in 1955 to 5,894 in 1956 and then to about 900 in 1959. But it would take almost a decade more—and the advent of Albert Sabin’s oral vaccine—to expand immunizations to cover not only elementary school children, but teenagers and adults too. Once Sabin’s vaccine was authorized for use in the U.S. in 1962, it is estimated about 100 million people, or about 56% of the American population at the time, received the oral vaccine over the next three years. Even then, polio was not declared eradicated in the U.S. until 1979.

The situation in the U.K. was even worse. When a serious safety issue arose with a batch of Salk’s vaccine in the U.S. (more on that in a moment), Britain decided it couldn’t rely on American-made supplies, and the government launched a crash program to produce doses domestically. But the British companies chosen for the task—Glaxo and Burroughs Wellcome—struggled to set up manufacturing capacity, with the latter taking years to complete its plant, says Gareth Millward, a historian at the University of Warwick who has written about the U.K. vaccination efforts.

Immunizations began in 1956, with Britain using its network of general practice, or family, doctors as the primary means of administering the inoculations. But inadequate supplies plagued the rollout, and in the summer of 1957 there was a major polio outbreak in the city of Coventry. This caused a public outcry that forced the government to reverse course and allow foreign-made vaccine doses to be imported and administered, Millward says. It then took until 1961 for most children in the country to be vaccinated. As for adults, that process took longer still, he says, although the tragic death of 29-year-old soccer star Jeff Hall from polio in 1959 spurred many adults to get immunized.

In comparison, the pace of today’s COVID-19 vaccination rollout does seem like “warp speed,” as the U.S. vaccine development funding program’s name suggests. “Overall, I think this is so much faster than the polio years; it’s really remarkable,” says Stephen Mawdsley, a history professor at the University of Bristol, in England, who has researched the U.S. polio vaccination drive.

In many ways, the polio vaccine effort was easier than what faces public health officials today, medical historians and health experts say. Schools provided an easy and convenient place to vaccinate most children, Offit says, and parents were so afraid of the ravages of polio they readily signed their kids up to be injected. With COVID-19, once immunization efforts move beyond the top priority groups of frontline health workers and nursing home residents into the next tiers, which are largely defined by age brackets, it becomes harder to identify locations that could readily serve as vaccination hubs, Offit says. “There is not a public health infrastructure for mass vaccination in the U.S., and we are trying to put that together on the run,” he says.

In an effort to head off a potential swine flu epidemic in 1976—which turned out to be much less of a threat than initially feared—the U.S. opened mass flu vaccination centers in convention centers and town halls and managed to immunize 40 million Americans in a matter of months, Offit says. There may be lessons to draw from here. Several U.S. cities are beginning to open up big public venues to serve as similar large-scale vaccination locations, and the U.K. has opened seven such centers and is promising a network of up to 50. But the problem with mass vaccination centers in the midst of a raging pandemic is that social distancing must be carefully maintained while people are waiting in line for their shots. “You don’t want the vaccination centers to become superspreader sites,” Schwartz says.

Another problem weighing on the vaccination drive this time that wasn’t a factor in the past: In many places, doctors and nurses are already working around-the-clock caring for hospitalized COVID-19 patients. They can’t easily be spared to give inoculations. In 1976, the flu vaccine was administered using a pneumatic gun, rather than a conventional needle and syringe. This allowed anyone, with a minimal amount of training, to safely and easily serve as vaccinators, Offit says.

Such technology is not currently being considered for the COVID-19 vaccines—in fact, the World Health Organization no longer recommends such jet injectors be used for vaccines because of safety risks—but figuring out ways to allow people without medical training to administer the vaccine may be crucial to increasing the speed of the immunization effort. In Britain, the government has begun recruiting volunteers from the general public who will be trained to give injections in the new mass vaccination centers to avoid further straining doctors and nurses. The U.S. plans to rely heavily on private pharmacies, particularly those owned by Walgreens and CVS, which between them represent some 20,000 sites around the U.S., Schwartz says. In the U.K., private pharmacies, which are already accustomed to providing seasonal flu jabs, have also told the government they could serve as vaccination hubs. Pharmacies also already have in place the kinds of technology—electronic databases and automatic text messaging—needed to help remind people to get their second doses of the vaccine at the right time, a significant concern given that experience with previous multi-dose inoculations in adults has shown that as many as a quarter of people fail to get their second jabs, Offit says.

Previous vaccination drives also took place amid a very different environment in terms of public anxiety around vaccinations. Surveys have shown that only about 60% of Americans intend to get a coronavirus vaccine, with many of those who are reluctant citing safety concerns as the reason for their hesitancy.

In contrast, the 1950s battle against polio succeeded despite a catastrophic safety problem in the first months of the immunization drive: Known as the Cutter Incident, it involved a batch of the vaccine, made by Cutter Laboratories, in which the live polio virus had not been properly inactivated. The vaccine resulted in about 40,000 cases of polio, including the deaths of 10 children and 200 others left with varying degrees of paralysis. Alarm over the debacle is what severely slowed the U.K. vaccination drive. But in the U.S., while vaccinations were suspended for three weeks while the March of Dimes and the U.S. government investigated and put new safeguards in place, the disaster had almost no discernible effect on people’s willingness to have their children immunized. “It is hard to imagine a vaccination program today surviving a safety lapse as bad as that,” Schwartz says. “Yet they got back on their feet within weeks.”

Another lesson from the polio eradication efforts was the importance of clear public health messages, and the use of celebrities, such as Elvis, who was vaccinated live on The Ed Sullivan Show in 1956, to build public confidence in the inoculations, Mawdsley says. But in today’s more fragmented popular culture, he says, public health officials should be “trying to identify different celebrities for different demographic groups” who can help promote vaccination.

It is also important to remember that our perceptions about what constitutes a successful immunization drive has changed significantly in the past half-century. “The idea that you can vaccinate everybody is a relatively modern phenomenon,” Millward says, noting that before the widespread use of computerized records in the 1980s and text messaging to mobile phones in the 1990s, such a goal would have been impractical. Today, he says, a 75% vaccination rate is seen as an abject failure, whereas in the 1950s it was seen as a brilliant success.

So today’s exasperation with the pace of the vaccine drive may seem misplaced by historical standards. But our impatience seems to grow in proportion to our technological capabilities.