Vaccination Coverage and Sudden Infant Death Syndrome

To the Editor In their Research Letter, Wolf et al described the recent increase in sudden unexpected infant death (SUID) in the United States between 2020 and 2022. The spike in SUID rates with an increase of nearly 12% after 3 decades of either decreasing or stable mortality rates is worrisome. The authors suggest infections such as COVID-19 and other respiratory illnesses, maternal opioid use, and changes in sleep-related factors as potential explanations. The abrupt increase does indeed point to external causes such as infections. Changes in sleep-related factors, on the other hand, seem less likely to have caused these swift changes. Sleep-related factors such as infant sleep position have remained fairly stable throughout the last decades. For example, a study investigating the prevalence of the nonsupine sleep position between 2016 and 2022 did not show a significant change in trends in the United States.