“Shocking” and “criminal” are not usually words medical specialists use when discussing a global pandemic.

But in recent days, some of the world’s top experts on COVID-19 have erupted in anger as the U.S., some European Union countries, and Israel roll out plans for vaccine booster shots—programs that infectious-disease experts warn could leave poor countries with deep shortfalls of doses, prolong the pandemic, and potentially spawn more dangerous coronavirus variants.

“We do not want to see widespread use of boosters for healthy people who are fully vaccinated,” the World Health Organization’s Director-General Tedros Adhanom Ghebreyesus said in Berlin on September 1, repeating the WHO’s earlier call for countries to delay their third-jab plans until next month, so that poor countries could work to catch up in their inadequately supplied vaccination programs.

“We still see shocking inequities in access to vaccines,” Dr. Tedros said.

Plans for booster shots have roiled the scientific community and governments around the world, as questions mount over how rich countries have been able to hoard excess vaccine doses while dozens of poor countries struggle to immunize more than a tiny percentage of people.

In just one example, the decision by U.S. authorities to start administering booster shots to millions of Americans beginning later this month reportedly prompted two top vaccine officials of the Food and Drug Administration to quit in protest on August 31.

In this highly combustable situation, vaccine manufacturers have made moves to increase production of COVID-19 doses—but in many cases for booster shots.

Pfizer has applied to the FDA for approval for its booster shot, marketed under the name Comirnaty, and in Europe, the European Medicines Agency last month approved two new Pfizer-BioNTech sites, in France and Germany, to manufacture booster shots. Moderna is scaling up production in Massachusetts and New Hampshire.

Deep divide

If anything, the deep divide between rich and poor countries has grown when it comes to COVID-19 vaccines.

About 75% of the world’s 5 billion vaccine doses so far have been administered in just 10 rich countries—a schism that could cost the global economy up to $2.3 trillion by 2023, according to a report last week by the Economist Intelligence Unit.

In France, for example, about 65.6% of the country’s 66 million are now fully vaccinated, after a major summer campaign to boost immunization rates. By comparison, a minuscule 2% of Africa’s 1.2 billion people are fully vaccinated.

Even so, on September 1 France became the first EU country to offer third-dose booster shots to anyone over 65—a program that even the EU’s own infectious-disease agency said on September 1 was unnecessary.

In July, Israel, where 60% of people are double-vaccinated with the Pfizer-BioNTech vaccine, became the first country to administer booster shots, which they offer to anyone over 60.

Those programs have ignited fierce criticism from leading scientists, who say the booster shots directly impact the vaccines available for poorer countries.

“You’re dealing with a finite, zero-sum resource,” renowned epidemiologist Bruce Aylward, a senior adviser to the WHO, told Science magazine last week. “You are reducing supply for those who need it more.”

Tulio de Oliveira, a biologist at the University of KwaZulu-Natal in Durban, South Africa, told the magazine that the booster shots were “unfair to say the least, potentially…even criminal.”

Booster shots might also be medically unnecessary, according to the European Center for Disease Prevention and Control. In a report on September 1, the EU agency said “there is no urgent need” for booster shots, unless people are in frail health. It said that people have apparently forgotten the purpose of vaccines: to prevent hospitalization and death. In that, the report says, two COVID-19 vaccine doses are “currently highly protective.”

Yet try telling that to regular citizens in rich countries like France, where COVID-19 vaccine doses are plentiful, given at local pharmacies or vaccination centers, and free of charge.

French President Emmanuel Macron drove a massive push to vaccinate the country after a sluggish start to its vaccine program last December—even mandating proof of full vaccination to enter restaurants and bars, museums, movie theaters, and shopping centers.

For many French, there seems no reason why not to receive a third jab.

“When you’re in good health and people around you are in good health, that’s what matters,” Bernard Weill, 68, CEO of the French clothing company Weill, told the Associated Press on September 1, sitting in a pharmacy in Paris’s Right Bank district, where he rushed to get his booster shot on the first day it was available. The vaccine jabs, he said, were “nothing to worry about and nothing to care about.”

Nothing to worry about, that is, for rich countries, and at least for now.