ba‐Giovanetti 2002.

Study characteristics
Methods	Case‐control study
Participants	Children and adolescents aged 14 months to 15 years from an Italian Local Health Agency with 12,880 residents of this age group Cases (N = 139): clinical mumps cases identified by national infectious diseases surveillance system within study area Controls (N = 139): randomly selected from immunisation registry, matched for birth year and address
Interventions	MMR (Urabe or Rubini or RIT4385‐Jeryl Lynn) vaccine exposure at least 30 days before disease onset (registry and phone interviews)
Outcomes	Association between MMR vaccine exposure and clinical measles within 30 days
Funding Source	Government
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
CCS ‐ case selection	Low risk	Clinical definition ‐ secure record ‐ representative series of cases
CCS ‐ control selection	Unclear risk	Randomly selected ‐ community
CCS ‐ comparability	Unclear risk	Possible residual confounding ‐ matched for birth year and address
CCS ‐ exposures	Unclear risk	Structured interview ‐ study did not distinguish between mumps strain (Urabe, Jeryl Lynn, and Rubini)
Summary Risk of Bias assessment	Unclear risk	We had concerns regarding at least 1 domain such that some doubt is raised about the results.