MMR Vaccination Coverage and Epidemiological Patterns in Al-Baha, Saudi Arabia, 2020-2024: Analysis of Suspected and Laboratory-Confirmed Cases.

BACKGROUND

High national MMR coverage in Saudi Arabia coexists with sporadic measles, mumps, and rubella cases. Local data are needed to describe vaccination coverage among the reported cases and patterns of laboratory-confirmed infections.

OBJECTIVES

This study was conducted to describe MMR vaccination coverage among the reported suspected cases and patterns of laboratory-confirmed measles, mumps, and rubella in Al-Baha, Saudi Arabia, from January 2020 to August 2024, and to examine associations between demographics, residence, vaccination status, and case classification.

METHODS

We conducted a retrospective analysis of surveillance records from the Al-Baha Communicable Disease Reporting System. We summarized the demographics, vaccination history, and final classification for 295 reported suspected cases. Inferential analyses (chi-square and logistic regression) used laboratory-confirmed cases only. Statistical significance was p < 0.05.

RESULTS

Of 295 reported suspected cases, 239 (81.0%) were discarded after investigation, and 52 (17.6%) were confirmed (including 50 laboratory-confirmed and two epidemiologically confirmed), with 3 (1.0%) remaining under review at analysis. Among all reported cases, the vaccination status was ≥2 doses, 57.6% (n = 170), one dose, 19.0% (n = 56), and unvaccinated/unknown, 23.4% (n = 69). Among the laboratory-confirmed infections, measles was clustered in unvaccinated/unknown, mumps was clustered in single-dose recipients, and rubella was in ≥2-dose recipients. In multivariable models, males had higher odds of a laboratory-confirmed infection, and rural residence was associated with increased odds. The confidence intervals were wide due to small numbers.

CONCLUSIONS

Reported surveillance data show persistent laboratory-confirmed MMR infections in Al-Baha with demographic and geographic disparities. The findings support targeted efforts to complete two-dose schedules, strengthen rural access, and improve immunization record systems. The results are associations and not causal measures of vaccine effectiveness, and should be interpreted in light of small confirmed case counts.