More than 14 million children did not receive a single vaccine last year — about the same number as the year before — according to U.N. health officials. Nine countries accounted for more than half of those unprotected children.

In their annual estimate of global vaccine coverage, released Tuesday, the World Health Organization and UNICEF said about 89% of children under 1 year old got a first dose of the diphtheria, tetanus and whooping cough vaccine in 2024, the same as in 2023. About 85% completed the three-dose series, up from 84% in 2023.

Officials acknowledged, however, that the collapse of international aid this year will make it more difficult to reduce the number of unprotected children. In January, U.S. President Trump withdrew the country from the WHO, froze nearly all humanitarian aid and later moved to close the U.S. AID Agency. And last month, Health Secretary Robert F. Kennedy Jr. said it was pulling the billions of dollars the U.S. had previously pledged to the vaccines alliance Gavi, saying the group had “ignored the science.”

Kennedy, a longtime vaccine skeptic, has previously raised questions the diphtheria, tetanus and whooping cough vaccine — which has proven to be safe and effective after years of study and real-world use. Vaccines prevent 3.5 million to 5 million deaths a year, according to U.N. estimates.