Some public-health disasters hit like hurricanes; others spread like rust. “We may not have a full picture yet,” Shah told me, referring to the latest evidence from the CDC on where vaccination rates are heading. “My gut and my clinical experience tell me that it’s too soon to say.”
Other experts share that view. Robert Bednarczyk, an epidemiologist at Emory University, has been estimating the susceptibility of U.S. children to measles outbreaks since 2016. National immunization surveys have not shown substantial drops in coverage for 2020 and 2021, he told me, “but there is a large caveat to this. These surveys have a lag time.” Any children from the CDC’s data set who were born in 2018, he noted, would have gotten most of their vaccines before the pandemic started, during their first year of life. The same problem applies to teens. The government’s latest stats for adolescents—which looked as good as ever in 2021—capture many who would have gotten all their shots pre-COVID. Until more data are released, researchers still won’t know whether or how far kids’ vaccination rates have really dipped during the 2020s.