Australian mumps serosurvey 2012-2013: any cause for concern?

Measles, mumps, rubella and varicella antibodies among international and domestic university students

BACKGROUND

Vaccine-preventable infections are generally well controlled in Australia. However, gaps in immunity can lead to outbreaks and are important to identify. Young adults are a highly mobile population and a potential source of imported infections. We aimed to evaluate anti- measles, mumps, rubella and varicella (MMR&V) IgG seroprevalence and explore factors relating to antibody seropositivity.

METHODS

A cross-sectional online survey was conducted among students from a large Australian university to collect demographic, vaccination, infection and travel characteristics. Blood samples were collected to measure MMR&V seroprevalence. Logistic regression was used to identify factors associated with seropositivity.

RESULTS

Among 804 university students, seroprevalence (positive or equivocal) for measles was 82.3% (95% CI 79.6-84.8%), mumps 79.5% (95% CI 76.7-82.3%), rubella 91.5% (95% CI 89.6-93.5%) and varicella 86.2% (95% CI 84.1-88.8%), with 452 (56.2%, 95% CI 52.8-59.6) seropositive to all four viruses. Varicella seropositivity was highest in the older birth cohort (born 1988-1991). Measles seropositivity was higher for international students compared to domestic students. Among international students, mumps seroprevalence was significantly lower than measles and rubella seroprevalence. International travel in the previous 12 months was reported by 63.1% of students, but only 18.2% of travellers reported seeking pre-travel health advice prior to most recent international travel.

CONCLUSIONS

Overall, this study suggests immunity to MMR&V is sub-optimal. We found the university student population to be highly mobile and unlikely to seek pre-travel advice; thus, they are a potential source of infection importation. The implementation of university immunization policies could address the gaps identified and our findings can inform the development of targeted vaccination campaigns.

Seroprevalence of mumps among children and adolescents in Thailand, 2020

Thailand has implemented single-dose mumps-containing vaccines since 1997 and two doses since 2010. This study aimed to describe the seroprevalence of mumps among children who received one- or two-dose mumps vaccines. A cross-sectional study of 145 children (aged 3-9 years) and 422 adolescents (10-18 years) was conducted. Mumps IgG seropositivity was defined as ≥ 22 RU/mL by EUROIMMUN ELISA method. The mumps seroprevalence was higher in children (82.1%, 95% CI 74.8-87.9) compared to adolescents (41.7%, 95% CI 37.0-46.6) who had received at least one dose of the mumps vaccine. Among those receiving 2 doses of mumps vaccine at ≥ 5 years after their last mumps vaccination, only 51.3% had maintained IgG ≥ 22 RU/ml. There was a reverse correlation between mumps IgG titer and the time interval from the second dose of mumps vaccine (R = -0.44, p < 0.001). A booster dose of MMR vaccine in young adults may be needed.