Updates can be found at the end of the article; the most recent update is from September 13, 2021.

In a press briefing Wednesday (August 4), Director General of the World Health Organization Tedros Adhanom Ghebreyesus implored countries to consider a temporary moratorium on COVID-19 booster shots—until at least the end of September—to allow countries with lower vaccination rates to catch up.

More than 80 percent of the vaccines distributed to date have gone to high and upper middle–income countries, Tedros notes, “even though they account for less than half of the world’s population.”

“I understand the concern of all governments to protect their people from the Delta variant, but we cannot and we should not accept countries that have already used most of the global supply of vaccines using even more of it while the world’s most vulnerable people remain unprotected,” he adds.

See “How the Second mRNA Vaccine Bolsters Immunity

Several nations, including Germany and Israel, have already rejected the idea of waiting, Reuters reports. “We want to provide the vulnerable groups in Germany with a precautionary third vaccination and at the same time support the vaccination of as many people in the world as possible,” the country’s health ministry tells the outlet. Israel began urging its older citizens to get booster shots at the end of July.

Other nations have similarly indicated plans to provide booster shots in the fall. French President Emmanuel Macron says the country is working on a roll-out plan for boosters in September, according to Reuters; the UK is also preparing to offer additional shots in September, The Washington Post reports.

While the United States has not yet decided whether boosters will be offered, White House press secretary Jen Psaki tells The New York Times that the Biden administration considers the juxtaposition of boosters with primary vaccinations to be “a false choice.”

“We can do both,” she adds, noting the administration’s efforts to distribute vaccines globally.

According to their developers, both the Pfizer-BioNTech and Moderna vaccines will likely need boosters to maintain protection, especially against the Delta variant. According to The Wall Street Journal, Moderna President Stephen Hoge says “a dose three of a booster will likely be necessary to keep us as safe as possible” in a business call Wednesday. “What we see is the potential for waning immunity.”

Public health experts continue to note that the likelihood of a vaccine-resistant variant emerging is higher in areas with low vaccination rates. “New variants are most likely to arise in unvaccinated populations," Ruth Karron, a medical doctor and epidemiologist with Johns Hopkins University, tells NPR. "So the more of the world that’s unvaccinated, the more we are all at risk."



Update (August 13, 2021): In the United States, people recovering from solid organ transplants and others with compromised immune systems are now eligible for a third shot of either currently authorized mRNA vaccine, the Food and Drug Administration announced yesterday. The Centers for Disease Control and Prevention’s independent advisory committee is expected to separately recommend the move in today’s meeting, reports The New York Times.

Whether boosters will become more widely available this fall remains an open question, Acting FDA Commissioner Janet Woodcock notes in the agency’s statement. “The FDA is actively engaged in a science-based, rigorous process with our federal partners to consider whether an additional dose may be needed in the future,” she says.

“Inevitably, there will be a time when we’ll have to give boosts,” National Institute of Allergy and Infectious Diseases Director Anthony Fauci tells NBC’s Today Show.

Update (August 17, 2021): The US Food and Drug Administration will recommend that mRNA COVID-19 vaccine recipients get booster shots eight months after their second dose of the vaccine, multiple outlets report. According the Associated Press, the announcement is expected as soon as this week. This means those who received their vaccinations in December 2020 and January 2021 could receive boosters as soon as mid-September, The New York Times reports; boosters will be with the same brands as the primary vaccinations.

Update (September 13, 2021): An opinion paper published in The Lancet today and coauthored by 18 vaccine experts argues that booster shots are unnecessary for most people. The paper comes as the debate among US officials over whether to offer boosters widely heats up; the Biden administration and the CDC appear to be at odds over the administration’s pro-booster stance, reports Politico.

Meanwhile, Tedros has extended his call for a booster moratorium, urging wealthier nations to postpone boosters until at least the end of the year. “I will not stay silent when companies and countries that control the global supply of vaccines think the world’s poor should be satisfied with leftovers,” he said in a news conference on September 8, reports the AP. “Because manufacturers have prioritized or been legally obliged to fulfill bilateral deals with rich countries willing to pay top dollar, low income countries have been deprived of the tools to protect their people.”