Vaccine orders are soaring into the billions of doses in much of the developed world, Covid-19 cases are easing, economies are preparing to roar to life, and people are busy planning summer vacations. However, in many less developed countries, the virus is raging, sometimes out of control, and vaccinations are far too slow to protect even the most vulnerable.

That split screen — clubs and restaurants reopening in the US and Europe while people in India gasp for air — was never meant to be so stark. Last year, 192 countries joined Covax, a vaccine-sharing partnership, and the Gates Foundation invested $300 million in an Indian factory to produce doses for the world’s poor. Last June, the European Union’s top executive stated at a global summit, “Vaccination is a universal human right.”

However, the virus is spreading faster than ever, thanks largely to gains in South America and India, and the global vaccination campaign is faltering.

In normal times, India is an important source of vaccines, but it has halted exports as it battles a record outbreak of the virus and an expanding humanitarian crisis. This has caused critical shipments to be delayed, with India producing the majority of Covax supplies.

In Brazil, where thousands are dying every day, officials have only received a tenth of the AstraZeneca doses promised by midyear.

And in countries as diverse as Ghana and Bangladesh, where initial vaccine supplies were depleted, the lucky few who received a first shot are unsure when they will receive another.

Many of the few doses that have been delivered are sitting in warehouses, with expiration dates rapidly approaching, due to a lack of funding for chronically underpaid health workers and vaccination training.

Despite global leaders’ determination to right past wrongs — most recently, a scarcity of swine flu vaccines in poorer nations during the 2009 pandemic — the challenges facing the current immunization campaign are formidable.

When the pandemic erupted last year, Covax was cash-strapped, making it impossible to compete for vaccine contracts with wealthier nations. Recently, the United States, the European Union, and India have prohibited at least some vaccine-related exports, leaving regions that do not manufacture their own doses reliant on those that do.

Even as richer countries immunize their own citizens, they may begin to save vaccine-making capacity for booster shots to deploy against new variants, which would be another blow to countries lacking manufacturing bases.

Analysts believe that Western nations should put pressure on vaccine manufacturers to collaborate with global manufacturing sites, regardless of how much it costs or how long it takes. It can be difficult to ramp up production in this manner, but surveys last year indicated that there was untapped capacity.

Covax has paid a high price for its reliance on shipments from India. According to planning documents saved by Zain Rizvi, a medicines access expert at Public Citizen, it forecast having 235 million doses by April and 325 million by May on its way to two billion doses this year, enough to vaccinate 20% of people in recipient countries.

However, by March, that forecast had been reduced by roughly one-third. Covax had shipped 54 million doses as of Tuesday, less than a quarter of its earlier April target. Gavi, the Vaccine Alliance, a public-private health partnership that co-leads Covax, stated that it was prioritizing second dose deliveries and urging richer countries to share vaccines.

While poorer countries scramble for supplies, many are also struggling to make use of the few doses they have. These operational failures, a rerun of what wealthy nations experienced months earlier, have resulted in vaccine stockpiles nearing expiration dates in countries that cannot afford to waste any doses.

The World Bank promised $12 billion for vaccine rollouts but has only approved $2 billion in projects so far. According to Mamta Murthi, the bank’s vice president for human development, the bank discovered in mid-March that less than a third of low- and middle-income countries reported having plans to train enough vaccinators or campaigns in place to combat vaccine hesitancy.