Quantifying the Long-Term Effects of Measles Infection - A Retrospective Cohort Study

Objective To assess whether measles infection has an impact on the rate of non-measles infectious diseases over an extended period. Methods This retrospective matched cohort study included 532 measles diagnosed patients which were exactly matched with 2,128 individuals with no previous measles diagnosis. Adjusted Odds ratio for any all - cause infectious diagnosis and any viral infection diagnosis, up to 2 years post measles diagnosis, between the measles and control groups was obtained from a conditional logistic regression model. Cox proportional hazards model was employed to estimate the hazard ratio. Results – Previous measles (MeV) exposure was associated with an increased risk for all-cause non-measles infectious disease diagnosis (OR = 1.83, 95% CI 1.26-2.64, p = 0.001), with 492 diagnoses in the MeV-exposed group and 1868 diagnoses in the control group. Additionally, previous MeV exposure was linked to a higher risk of viral infection diagnosis (OR = 1.23, 95% CI 1.01-1.59, p < 0.05), with 302 viral infection diagnoses in the MeV-exposed group and 1107 diagnoses in the control group. The hazard ratio for viral diagnosis in the MeV-exposed group compared to the control group was 1.54 (95% CI 1.18-2.02, p < 0.001). Conclusion Individuals diagnosed with measles had a moderate increased risk of being diagnosed with all cause non-measles infectious disease or viral infection. This observational individual level study supports previous ecological and individual population level studies.