Sorup 2019.

Methods	Cohort study
Participants	295,559 children born in Denmark from April 2004 to December 2010. The cohort were followed from age 47 months (1 month before turning age 4 years, which is the recommended age of the second MMR (MMR‐2)) until age 60 months.
Interventions	MMR vaccination second dose
Outcomes	Antibiotic prescriptions and hospital admissions for any off‐targeted infection
Notes	Conclusion: in this study, revaccination with MMR appeared safe with regard to off‐target infections and was associated with a lower rate of severe off‐target infections. More studies of the possible association between revaccination with live attenuated vaccines and off‐target infections are needed.

AEFI: adverse events following immunisation
CI: confidence interval
HAEs: hypersensitivity‐type adverse events
MMR: measles, mumps, rubella vaccine
OR: odds ratio
PEP: postexposure prophylaxis