In Guatemala, shortages of syringes have slowed vaccination efforts. In Haiti, logistical and security challenges after the devastating Aug. 14 earthquake have contributed to making it the country with the lowest vaccination coverage in the world.

And across the Caribbean, countries are grappling with unequal distribution of doses and vaccine hesitancy, World Health Organization officials warned today in an online news conference.

In the first months after the vaccine rollout, Black Americans were far less likely than white Americans to be vaccinated. In addition to the difficulty of obtaining shots in their communities, their hesitancy was fueled by a powerful combination of general mistrust of the government and medical institutions, and misinformation over the safety and efficacy of the vaccines.