Fragmented, decentralized health system plagues vaccine rollout across US, Mass.

Jerome Sampson helped his mother, Lorraine Peters, 80, get vaccinated at Gillette Stadium.David L. Ryan/Globe Staff

The snakebitten COVID-19 vaccine launch, beset by supply shortages, unused doses, and vexing technical complexity, has brutally exposed the weaknesses in the fragmented US and Massachusetts health care delivery systems.

Global data show the United States badly trailing the United Kingdom, which has a more centralized health care system, in getting people immunized. Relying on its vaunted National Health Service, which provides care for virtually the entire nation, the UK had vaccinated 13.7 percent of its population by Monday, while just 7.8 percent of Americans had received shots, according to the University of Oxford.

The problems plaguing the US vaccination drive — decentralization, lack of coordination, and consumer confusion — are especially stark in Massachusetts, which ranks 34th nationally in per-capita vaccinations, the Centers for Disease Control and Prevention reported Tuesday.

Other populous states with similarly dispersed health systems, such as California, Illinois, and Texas, are also mired in the bottom half of the CDC rankings. Many distributed much of their early allotments through big hospitals and long-term-care facilities, leaving no central player in control of the process.

“There’s no question that the fragmentation of the American health system has subverted every stage of our ability to respond to COVID,” including vaccinations, said Andrew Dreyfus, chief executive of Blue Cross Blue Shield of Massachusetts, the state’s largest health insurer.

While a lack of central planning by the Trump administration handicapped every state, many have made their own mistakes preparing for vaccinations. Massachusetts officials have had to halt shipments to sites with doses sitting on freezer shelves while fielding a stream of complaints from residents unable to book vaccine appointments. They are scrambling to open a call-in line and streamline an online registration portal.

Centrally organized systems — seen in smaller countries like Israel and the United Arab Emirates that have vaccinated a third or more of their residents — are immunizing people more quickly, said Jen Kates, a senior vice president and global health policy director at the Kaiser Family Foundation.

“In the United States, the federal government has punted to the states, and the states have punted to counties or hospitals,” Kates said. “But when you’re in a pandemic, the viral agent you’re trying to fight doesn’t care if you’re in one state or another or one health system or another.”

By setting national priorities about who gets vaccinated first, other countries have also avoided the patchwork of priorities set by US states that almost guarantees that residents ineligible for shots in one state will know people of a similar age or risk factor who are able to get shots first in another.

Massachusetts is trying for a reset this week as the state moves into the second phase of its rollout, where larger segments of the population will be eligible for vaccines starting with about 450,000 residents age 75 and over.

Governor Charlie Baker defended the state’s performance at a briefing Monday, saying other states have been able to vaccinate more residents because they’ve been less scrupulous in giving priority to those at highest risk.

“I don’t believe there’s been another state that made a commitment to vaccinate all the folks who live in group homes and homeless shelters, who are developmentally disabled, who are dealing with mental health issues,” he said. “We’re one of a very small number of states that actually said we wanted to vaccinate all of our front-line health care workers first out of the gate. Because we chose some of those routes to begin with, we knew it was going to [take] a little longer.”

But critics of the Massachusetts rollout say it relied too heavily on big hospitals and paid too little attention to what state Attorney General Maura Healey called the “operational nitty gritty” needed to efficiently direct residents to injection sites.

“This was a total debacle, and it was unnecessary,” Healey said in an interview, noting her office has received a steady flow of complaints. “I don’t understand why a state that leads the nation in technology, that leads the nation in health care, wasn’t able to build a website that made it easy for people to enroll. What we need right now is transparency, communications, and a clear plan.”

Massachusetts officials have not disclosed specific dates when each group of residents, classified by age or risk, will become eligible for vaccine. Nor have they given a target date for reaching their goal of vaccinating 4 million adult residents, saying that will hinge on federal shipments. They say they’re working to improve the clunky signup process.

“We continue to make adjustments to the website,” Baker said Monday. He said new features make it easier for residents to search by geography to register for injections. Baker added that “we’ve been doing a fairly decent look at the way these sites operate in other states and are going to try to incorporate what we think of as some of the best practices.”

While initial shipments to states were slow and unpredictable, the Biden administration has said federal vaccine allotments will increase in the coming weeks. Doses will be distributed more widely in Massachusetts, through mass vaccination sites, community sites, doctors’ offices, and retail pharmacies.

Analysts who have closely tracked the vaccine rollout say states with large hospital systems, such as Massachusetts, New York, and Pennsylvania, sent the bulk of vaccine shipments to them in the early weeks, taking a “hospital-centric” approach that effectively delegated distribution.

States turned to hospitals partly because of the urgency of immunizing front-line health workers — and partly because they had ultracold freezers that could store the Pfizer vaccines that were first off the production line.

But all across the country, states are struggling to fully utilize the doses they’ve been given as more health workers than expected have declined shots. CDC figures show 42 percent of the nearly 1.1 million vaccine doses Massachusetts had received as of Monday were sitting in freezers.

The hospitals strictly followed state priorities when they had unused doses, declining to give them to residents not yet eligible, even if being more flexible might have hastened vaccinations. In Massachusetts, hospital representatives played a leading role on the advisory panel that set the state’s priorities, which started with front-line hospital workers.

“In large states like Massachusetts, strictly adhering to the planned protocol has slowed distribution,” said Eric Schneider, senior vice president for policy and research at the Commonwealth Fund. “You need a combination of flexibility and adherence to protocol.”

Given only a few days’ notice when more shipments would arrive, hospitals kept many vials in their freezers, earmarked for second doses to workers who received first shots.

“If you think the supply is going to dry up, the safest strategy is to hold the second doses,” Schneider said.

In the UK, by contrast, providers are giving shots to as many residents as possible even if it means they will have to wait longer than four weeks for second shots.

UK health providers also capitalize on “real-time situational awareness of the population” to quickly schedule shots, Schneider said. “They know exactly who they’re reaching in a way that’s impossible in the US.”