Delay in measles vaccination is associated with increased risk of post-vaccination seizures

摘要

Main Results In the analysis of any measles-containing vaccines, the increased risk of seizures during the 7- to 10-day risk interval, using the remainder of the observation period as the control interval, was significantly greater among older children (relative risk, 6.5; 95% CI, 5.3-8.1; attributable risk, 9.5 excess cases per 10 000 doses; 95% CI, 7.6-11.5) than among younger children (relative risk, 3.4; 95% CI, 3.0-3.9; attributable risk = 4.0 excess cases per 10 000 doses; 95% CI, 3.4-4.6). The relative risk of post-immunization fever was significantly greater among older children than among younger children; however, its attributable risk was not. In the analysis of vaccine type, the measles, mumps, rubella, and varicella vaccine was associated with a 1.4-fold increase in the risk of fever and 2-fold increase in the risk of seizures compared with the measles, mumps, and rubella vaccine administered with or without a separate varicella vaccine in both younger and older children.