The CDC just reported steep declines in the number of American children receiving their routine immunizations. Data from the Vaccines for Children Program (which provides one-half of federally purchased vaccines) and the Vaccine Safety Datalink, find that the US national COVID19 emergency declaration on March 13, 2020 triggered a sudden drop in childhood vaccinations. Within weeks, parents ceased bringing their children in to see their pediatrician or family healthcare provider [1](Fig. 1). The steepest declines included measles-containing vaccines. We already know that an accelerated antivaccine movement caused the return of measles to the United States in 2019 [2], resulting in multiple epidemics and more than 1200 cases [3]. It then strengthened during the first months of 2020 as evidenced by protests against vaccines on state capitals in New Jersey, Connecticut, and elsewhere [4, 5].

Is this temporary, or can we expect measles or other vaccinepreventable diseases to continue rising? The CDC trends show that vaccinations among young children less than 24 months are beginning to rebound, although they remain suppressed among older children. This means that this year’s cohort of preschool children may not receive their second dose of measles vaccine making outbreaks more likely.