serological survey of measles, mumps and rubella immunity among school aged children in Western Saudi Arabia

To evaluate the adequacy of measles, mumps and rubella [MMR] vaccination among children and to assess risk of outbreak in Jeddah, Kingdom of Saudi Arabia [KSA]. We recruited a total of 527 children from schools located at different urban regions, and preschool children from those attending the well baby clinics in Jeddah, KSA. We tested for MMR viruses antibodies using ELISA technique. Approximately 99% of children received MMR vaccine. Overall seropositivity for measles antibodies was 71%, mumps 65% and rubella 90%, which were elevated in vaccinated versus non-vaccinated children [p<0.000]. In vaccinated children, percentage of seropositivity for MMR was higher in public school children versus private [p<0.01] or those who did not attend school [p<0.01] and in Saudi versus non-Saudi children [p<0.000]. In vaccinated children, percentage of seropositivity obtained according to age groups of 4-6 years for measles was 73.7%, for mumps 66.7% and for rubella 91.7%. As for 7-11 years age group, seropositivity for measles was 72.6%, for mumps 68.1% and for rubella 93%, while for the 12-14 years, seropositivity for measles was 66.4%, mumps 59.1% and for rubella 86.1%. The prevalence of seropositivity against the above-mentioned viruses decreased with progression of age. Measles, mumps and rubella mass vaccination program achieved high coverage rate among children, in Jeddah, KSA. However, there is still a high level of sera negative children among vaccinated ones for measles and mumps. Seropositivity decreased with age, which might raise possibility of outbreaks among adolescent. Additional doses of vaccine against measles and mumps are recommended and evaluation of new MMR protocol should be made