We evaluated the relationship between routinely administered childhood vaccines and nontargeted infectious disease hospitalizations in a large population-based cohort study. We specifically tested 2 hypotheses: whether multiple-antigen vaccines increase the risk of nontargeted infectious diseases, and whether aggregated vaccine exposure increases the risk of nontargeted infectious diseases. Of the associations between specific vaccines and nontargeted infectious disease hospitalizations, we found an adverse association between the Hib vaccine and acute upper respiratory tract infections. This association, if causal, has limited clinical relevance because of the modest magnitude of the effect. It also has no bearing on the specific hypothesis tested due to Hib being a single-antigen vaccine. However, the association is unlikely to be causal because it did not present as either a temporal effect or a dose-response effect. Furthermore, this 1 adverse association of a possible 42 is within the limits of what would be expected purely by chance in a study with multiple comparisons at this level of statistical significance. Conversely, the 15 observed protective associations suggest that vaccination may have nontargeted protective effects. When considering aggregated vaccine exposure, we found no adverse associations between an increasing number of vaccinations and nontargeted infectious disease hospitalizations. Overall, our results support neither of the tested hypotheses.
Odgovori s citatom