ABUJA, Nigeria — Ghana became the first country to receive a shipment of coronavirus vaccine from a global effort to equitably distribute doses after a plane landed Wednesday with 600,000 AstraZeneca shots.

The rollout is a first step toward getting doses to low- and middle-income countries cut out of the global vaccine race. But the timing and the relatively modest supply — enough for just 1 percent of Ghana's population — point to major challenges in the immunization effort.

More than 190 countries signed up to participate in Covax, a multilateral effort to develop and distribute coronavirus vaccine doses, but the initiative has struggled to secure enough as wealthy countries snapped up a disproportionate share of early supply.

President Biden last week pledged $4 billion to the effort, reversing the Trump administration's decision to opt out. Yet the United States and other wealthy countries have so far resisted calls to give doses, rather than funding, to countries in greatest need.

"We will not end the pandemic anywhere unless we end it everywhere," World Health Organization head Tedros Adhanom Ghebreyesus said Wednesday, according to a Covax news release. "Today is a major first step towards realizing our shared vision of vaccine equity, but it's just the beginning."

Covax aims to distribute 2.3 billion doses by the end of 2021 — a significant amount but still well short of demand.

Ghana, a country of 31 million, was selected as the first recipient after sending a rollout plan to Covax proving its health-care teams and cold-chain equipment were ready to support a quick distribution. The Ivory Coast and other countries in the region are expected to receive similar shipments soon.

The doses touching down in the capital, Accra, came from the Serum Institute of India, the world's largest vaccine manufacturer.

Boxes of vaccine left Mumbai on Tuesday for Dubai, where a logistics crew picked up hundreds of thousands of syringes, before hurtling toward Africa’s west coast.

“In the days ahead, front line workers will begin to receive vaccines, and the next phase in the fight against this disease can begin — the ramping up of the largest immunization campaign in history,” Henrietta Fore, executive director of the United Nations Children’s Fund, said in a statement.

Ghana kicked off its rollout months behind wealthier nations, highlighting the deep disparities of shot distribution as the pandemic throttles life around the globe.

The organizations running Covax — the World Health Organization, the Coalition for Epidemic Preparedness Innovations and Gavi, the Vaccine Alliance — have battled to secure funding, particularly after the Trump administration spurned the effort, in part because of its feud with the WHO.

The impact of the Biden administration’s support will probably be felt over the mid- to long-term but is unlikely to help with the urgent and immediate task of getting doses to front-line workers in low- and middle-income countries.

French President Emmanuel Macron last week suggested that the United States, Europe and other wealthy buyers should give 4 to 5 percent of their current vaccine supplies to developing nations in an immediate show of goodwill and commitment.

But the United States has so far steered clear of making any such commitment, focusing instead on vaccination efforts at home.

The African Union is pushing to inoculate 60 percent of the continent’s 1.3 billion people over the next three years, but soaring global demand — coupled with the weaker buying power of poorer nations — have delayed this objective.

The body said it has obtained 670 million doses of AstraZeneca, Pfizer and Johnson & Johnson vaccines for 54 countries. Several countries, meanwhile, are negotiating vaccine packages with China and Russia. Most still rely on the Covax support.

Health officials warn that uneven access to vaccines will prolong the pandemic, spawning variants that are harder to tame.

The variant first seen in South Africa, which is far more transmissible, has been detected in Ghana and several other nations, fueling devastating second waves across the continent.

“There is so much stress now with the second strain of this disease,” said Rebecca Kumah, a nurse who treats covid-19 patients on the night shift in Accra. “The fight is still on. As health-care workers in the line of duty, the vaccines are a great relief.”

By Wednesday, Ghana had recorded more than 81,000 coronavirus cases and 580 deaths.

Ghana plans to first protect the vulnerable: health-care personnel, the elderly and those with medical conditions that increase their risk of serious illness. The first shots will be administered early next week.

More than 300,000 community health workers have received vaccine distribution training in the coronavirus era, health officials said.

The goal is to eventually vaccinate 20 million people, Kwame Amponsa-Achiano, Ghana’s program manager for immunization, told reporters this month. However, it is unclear how long that effort could take.

“There is hope in sight,” said Juliette M. Tuakli, a public health physician and pediatrician in Accra. “People have underestimated the enormous mental health toll covid has taken on everyone. We never thought we’d be dealing with this a year-plus later.”