Among children from 24 through 47 months of age with emergency department (ED) and inpatient visits for infectious diseases not targeted by vaccines, compared with children without such visits, there was no significant difference in estimated cumulative vaccine antigen exposure through the first 23 months of life. This according to a nested case-control study conducted in 6 US health care organizations participating in the Vaccine Safety Datalink. Cases of non-vaccine-targeted infection were matched to controls by age, sex, health care organization site, and chronic disease status. Participants were children ages 24 through 47 months, born between January 1, 2003, and September 30, 2013, followed up until December 31, 2015. Investigators found:

• Among the 944 patients (193 cases and 751 controls), the mean (SD) age was 32.5 (6.3) months, 422 (45%) were female, and 61 (7%) had a complex chronic condition.
• Through the first 23 months, the estimated mean (SD) cumulative vaccine antigen exposure was 240.6 (48.3) for cases and 242.9 (51.1) for controls.
• The between-group difference for estimated cumulative antigen exposure was −2.3.