Field evaluation on protection efficiency of mumps containing vaccine in mumps outbreaks in schools in Lu′an

Objective To evaluate the protection efficiency of mumps containing vaccine (MuCV) and provide evidence for the improvement of mump immunization strategy.

Methods A retrospective cohort study was conducted among all school students during the mumps outbreaks occurred in Lu'an from 2015 to 2016.

Results The protection efficiency of 2 dose MuCV was better than that of 1 dose, the protection efficiency of 1 dose, 2 dose and 3 dose MuCV were 49.35% (95% CI: 36.03%–59.89%), 66.04% (95%CI: 45.54%–78.83%) and 85.96% (95%CI: 1.80%–97.99%), respectively. This data showed the 2 dose MuCV vaccination had highest protection efficiency of 78.68% at an interval of 3–4 years between the 1^st dose and the 2^nd dose (95% CI: 34.30%– 93.08%). The protection efficiency of 1 dose MuCV decreased with time, which was 72.78% within 4 years (95%CI: 39.29%–87.29%), 52.73% during 4–6 years (95%CI: 38.31%–63.79%) and 27.67% after more than 10 years (95%CI: –24.15%–57.86%). Vaccination with 1 dose of measles-mumps-rubella(MMR),measles and mumps combined vaccine(MM) or monovalent mumps vaccine (MuV) could provide better protection within 4 years. However, the cumulative risk of mumps was higher in MMR vaccination group than those in MM or MuV vaccination groups.

Conclusion The protection efficiency of MuCV decreased with time, and the protection efficiency was best within 4 years after vaccination. The protection efficiency of 2 dose MuCV was better than that of 1 dose, and the highest protection efficiency could be achieved at an interval of 3–4 years. It is suggested to implement 2 dose MuCV immunization strategy as soon as possible.