ABIDJAN, Ivory Coast — Health leaders in Ivory Coast were thrilled when the first half-million coronavirus vaccine doses arrived in late February. But that excitement cooled to concern as the West African country’s rollout collided with a lack of demand.

By March 30, the nation of 26 million had doled out 40,153 shots — well short of the monthly output needed to stay on schedule before the AstraZeneca vials expire in September.

“I admit that I am stressed,” said Daniel Ekra, the epidemiologist in charge of Ivory Coast’s vaccination program. “There is pressure. Because if you look at our country and say, ‘you had 500,000 doses that you didn’t use,’ it is not worth sending you another 1.5 million doses.”

Ivory Coast was the second African nation to receive shipments this year from Covax, the global effort to equitably distribute vaccine doses, and is expecting another batch in May.

The initiative has been the continent’s top supplier as African countries face particularly severe shortages: 39 have administered a total of 11.2 million shots thus far, according to the World Health Organization, while the United States alone has given out more than 207 million.

Ivory Coast is lagging behind neighbors that launched rollouts within the same few days. Ghana and Senegal have already distributed most of their first batches, at least 522,000 and 294,000 doses, respectively. Preregistration campaigns backed by aggressive outreach fueled that success, experts say.

Rollouts elsewhere are running into a variety of problems.

In Liberia, news of the AstraZeneca suspensions in Europe delayed the distribution of doses by about three weeks, said Wilhemina Jallah, the nation’s health minister. The country of 5 million received 96,000 Covax doses on March 6.

“We had to wait a bit,” Jallah said. “We had to do damage control. Now we are letting people know they are safe. It has made it more difficult for us.”

South Sudan — which received 132,000 doses from Covax on March 25 — was supposed to start injections last week, said Kawa Tong, a public health physician in the capital, Juba, but the government postponed the inoculation campaign without specifying why.

“The more delay, the more people will relax,” she said, “and the rainy season starts this month. With the floods, it will be harder to reach them.”

A shortage of health-care workers across the continent is also slowing vaccine deliveries in several nations, experts warn. Communities in sub-Saharan Africa have only 0.2 doctors for every 1,000 people, according to World Bank data — compared with the worldwide average of 1.6.

And distribution data is frequently delayed. Ethiopia and Sudan, for instance, have launched their inoculation drives but have released no numbers on how many shots are making it into arms.

The push in Ivory Coast is plagued by a pervasive hesitancy, officials say.

“There has been a kind of systematic refusal of the vaccine,” said Ekra, the Ivorian vaccine official, “because people thought Africans would be used like guinea pigs.”

Ivorians have expressed doubts about safety, pointing to the widely shared comments of a French doctor who suggested last spring that coronavirus-fighting drugs should be first tested on Africans.

The grim history of medical experimentation on the continent is cited in videos blazing across WhatsApp, warning viewers to steer clear of drugs from abroad.

Some don’t trust the AstraZeneca doses, specifically — the bulk of the Covax supply — after the suspensions in Europe over blood clot concerns. (Health watchdogs assert that risk is low.)

“People rely too much on social networks to do their research,” said Modeste Assi, a nurse at Ivory Coast’s busiest vaccine center in the commercial capital, Abidjan. “They also see what is happening in Europe and on the international level and that makes them scared. There is a danger that we don’t use all of the vaccines.”

A recent Afrobarometer poll of five West African countries — Benin, Liberia, Senegal, Niger and Togo — found that only 4 in 10 respondents said they’d consider getting a dose.

In Ivory Coast, the government is scrambling to boost interest with social media campaigns and Facebook Live events. Scientists are scheduling meetings with influential religious leaders, hoping to sway followers.

“There is a serious risk that if we are not using these doses with short shelf lives, it will be a waste and a tragic waste,” said Richard Mihigo, coordinator of immunization and vaccine development for the WHO’s Africa arm.

Planners had assumed the 500,000 initial doses would go quickly in Abidjan, which is home to 95 percent of recorded infections. Ivory Coast had counted 44.326 cases and 247 deaths by Friday.

They felt ready. The original expiration date on the vials was in June, before regulators in India, home to AstraZeneca’s top manufacturer, said the doses could be stored for nine months instead of six.

To receive the first shipment from Covax, the country had to prove it could support a rollout with trained workers and adequate storage. Patrick Achi, the nation’s prime minister, received the country’s first jab on live television.

Leaders aimed to vaccinate at least 2 million people by the end of the year.

The nation opened about 50 vaccination sites. At first they prioritized health workers, soldiers, police officers and teachers. Then anyone older than 50 or suffering from a chronic medical condition could show up. Then — on Monday — any adult.

Yet the short clinic lines have persisted.

On a recent afternoon, a few dozen people were waiting for the needle inside a white tent outside the Palais des Sports, an arena in Abidjan. About 450 would get a dose that day.

One was Oulahi Adeka, a 27-year-old theater prop designer, who wanted to avoid the illness that struck a few people she knew.

“My friends told me I was crazy,” Adeka said. “But I told them that if I don’t die from having this vaccine, then they need to come and get vaccinated, too.”

They’re worried about being guinea pigs, she added.

“Many people say the coronavirus doesn’t exist,” Adeka said, “or that this vaccine rollout is all about Europeans coming to do tests on Africans.”

Across town, Ludovic Mambé, a 56-year-old construction worker, said he has no plans to sign up.

“In France, they banned the vaccine,” he said, referencing the European country’s AstraZeneca suspension. “If other countries don’t take the vaccine, why should we?”