Objective: Mumps-containing vaccine is currently not a component of the national immunization schedule in Lao People's Democratic Republic (PDR). Mumps itself is not a notifiable disease in the country and the seroprevalence of anti-mumps immunoglobulin G (IgG) in the general population is unknown. In this study, anti-mumps IgG was measured in 2058 blood samples to evaluate population immunity in the country.
Results: The seroprevalence of anti-mumps IgG showed a gradual increase with increasing age, starting at 10.6% (95% CI 7.4-13.7) in participants aged 1-2 years, and almost plateaued at about 75% in individuals older than 11-12 years, though it still tended toward a small increase up to 89.6% (95% CI 86.6-92.6) in participants aged 40 years or older. Compared with the results of previous studies, this increase with increasing age is less marked and the plateau of anti-mumps seroprevalence is lower. We attribute this result mainly to the lower population density in Lao PDR.
Keywords: Mumps; Nationwide cross-sectional population-based survey; Pre-vaccination era; Seroprevalence.