IMPORTANCE: In low-income countries, live measles vaccine reduces mortality from causes other than measles infection. Such nonspecific effects of vaccines might also be important for the health of children in high-income settings. OBJECTIVE: To examine whether the live vaccine against measles, mumps, and rubella (MMR) is associated with lower rates of hospital admissions for infections among children in Denmark. DESIGN, SETTING, AND PARTICIPANTS: Population-based cohort study of Danish children born 1997-2006 and followed up from ages 11 months to 2 years (last follow-up, August 31, 2008). Nationwide Danish registers provided data on vaccinations and hospital admissions. The recommended vaccination schedule was inactivated vaccine against diphtheria, tetanus, pertussis, polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) administered at ages 3, 5, and 12 months and MMR at age 15 months. MAIN OUTCOMES AND MEASURES: Incidence rate ratios (IRRs) of hospital admissions for any infection, comparing receipt of MMR vs DTaP-IPV-Hib as the most recent vaccine. Risks, risk difference, and number needed to vaccinate were calculated for receiving MMR on time. RESULTS: The study included 495 987 children contributing with 56 889 hospital admissions for any type of infection during 509 427 person-years (rate, 11.2 per 100 person-years). Receiving the live MMR vaccine after the inactivated DTaP-IPV-Hib-vaccine was associated with a lower rate of hospital admissions for any infection. (Table Presented) The risk of admission for an infection between ages 16 months and 24 months was 4.6% (95%CI, 4.5%-4.7%) for receiving MMR on time and 5.1% (95%CI, 5.0%-5.2%) for not receiving MMR on time. The risk difference was 0.5 percentage point (95%CI, 0.4-0.6), and the number needed to vaccinate with MMR before age 16 months to prevent 1 infectious disease admission was 201 (95%CI, 159-272). CONCLUSIONS AND RELEVANCE: In a cohort of Danish children, receipt of live MMR vs inactivated DTaP-IPV-Hib as the most recent vaccine was associated with a lower rate of hospital admissions for any infections. These findings require replication in other high-income populations. Copyright 2014 American Medical Association. All rights reserved.
