Effect of gender on reporting of MMR adverse events in Saudi Arabia.

We evaluated the safety of a measles-mumps-rubella (MMR) immunization campaign for Saudi children (age range: 6-13 years) and gender differences in reporting post-MMR adverse events. After vaccinations were administered, we monitored 160 schools for 14 days and 19 hospitals in the 8 cities under study for 10 weeks. Incidence rates were: all MMR adverse events, 26.5/10,000 MMR vaccines (significantly higher in females than males); Urabe strain aseptic meningitis, 1.0/295,000; fever, 40.2/10,000 (females) and 0.9/10,000 (males); and parotitis, 5.4/10,000 (females) and 0.9/10,000 (males). Combined MMR vaccine containing the Urabe mumps strain was safe for children aged 6-13 years. Gender differences regarding reactogenicity were evident and should be considered when designing future studies.