Seroprevalence of measles, mumps and rubella among young adults, after 20 years of universal 2-dose MMR vaccination in Israel.

Evidence-based vaccination policy is important for the global and local efforts of achieving control over measles. In 2007, the first Israeli birth cohort to be twice vaccinated during childhood with Measles-Mumps-Rubella vaccine reached adulthood. In parallel, Israel experienced its largest measles outbreak since 1994. We aimed to assess the seroprevalence of measles IgG antibodies and concordance with rubella and mumps seroprevalence among young Israeli adults born 1988-9 in comparison to previous birth cohorts, in order to inform evidence based prevention policy. We conducted a seroprevalence study of IgG antibodies among 439 Israeli adults born in 1988-9, based on a representative sample of sera collected at age 18-19 upon recruitment to mandatory military service in 2007. In total, 85.7% were seropositive for measles as compared with 95.6% in the 1996 recruitment (P < 0.001). The absolute decline was significant both for males (8.8%, P = 0.001) and females (12.1%, P < 0.001). There were no significant differences in seropositivity by gender, years of education, country of birth or smoking status. Rubella seropositivity among measles seropositives was 90.4%, significantly (P < 0.001) higher than 72.1% among measles seronegatives. Mumps seropositivity among measles seropositives was 87.0%, significantly (P < 0.001) higher than 62.3% among measles seronegatives. Results were similar for Israeli-born only. Our findings indicate that measles seroprevalence decreased after the last change in vaccination policy and reach sub-optimal level. Until global eradication is reached, a proactive vaccination program to supplement routine childhood vaccination program should be considered in Israel and in other countries.

Rubella seroprevalence in the first birth cohort reaching fertility age after 20 years of two dose universal vaccination policy in Israel.

BACKGROUND: A national program of a 2-dose universal childhood MMR vaccination policy has been in effect in Israel since 1988. As the 1988 birth cohort reached fertility age, questions regarding immunity against rubella were raised. OBJECTIVE: To assess the seroprevalence of rubella IgG antibodies among young Israeli adults born after 1987 in comparison to previous birth cohorts, in order to determine evidence based policy for prevention of rubella and congenital rubella syndrome. METHODS: We conducted a seroprevalence study of rubella IgG antibodies among 416 Israeli adults (42.5% females) born in 1988-1989, based on a representative sample of sera collected at age 18-19 upon recruitment to mandatory military service in 2007. RESULTS: In total, 87.7% were seropositive (>15 IU/ml) as compared with 84.8% in the 1999 recruitment (P=0.26) and 93.4% in 1987 (P=0.004). Yet there was a difference by gender. The proportion of seropositives among female young adults (92.7%) was significantly lower as compared to those measured in the 1999 (99.2%, P=0.001) and 1987 (99.0%, P=0.006) recruitments. The proportion of seropositives among males (84.1%) was significantly higher as compared to those measured in 1999 (73.0%, P<0.001) but similar to those of 1987 (88.8%, P=0.13). Females born in the FSU were found to be high risk groups as 11.5% were seronegative. CONCLUSIONS: Our findings indicate that despite a successful program of congenital rubella syndrome prevention in Israel, there is a decline in seroprevalence among female young adults, especially immigrants from the FSU. A proactive catch-up program for females, especially for those of higher risk for susceptibility should be considered in Israel and in other countries.

Seroepidemiology of Epstein-Barr virus and cytomegalovirus among Israeli male young adults.

PURPOSE: To assess the seroprevalence and seroconversion of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) Immunoglobulin G (IgG) antibodies and identify associated socioeconomic and smoking variables among male young adults in Israel, to explore health disparities and aid prevention efforts. METHODS: A population-based seroprevalence study of EBV and CMV IgG antibodies in a systematic sample of Israeli males upon recruitment to mandatory military service during 1994-2004. Associations between socioeconomic and smoking variables and the seroprevalence of EBV/CMV were evaluated, controlling for possible confounders. A subset of seronegative subjects was assessed for seroconversion upon discharge from military service. RESULTS: Overall seroprevalence rates were 87% for EBV and 59% for CMV. An association between the seroprevalence of EBV and CMV was observed. Seroconversion was 56% for EBV as compared with 31% for CMV. Lower paternal education was found to be associated with both EBV and CMV seroprevalence. Lower socioeconomic status, North African origin, and urban residence were found to be associated with CMV seropositivity, as was smoking for EBV seropositivity. CONCLUSIONS: Socioeconomic disparities exist in the seroprevalence rates of CMV and EBV among Israeli male young adults. The results of the study could aid public health efforts and determine target populations when a vaccine becomes available.

Sub-optimal prevalence of mumps antibodies in a population based study of young adults in Israel after 20 years of two dose universal vaccination policy.

BACKGROUND: A recent mumps outbreak in Israel despite an ongoing national program of a 2-dose universal childhood vaccination policy since 1988, raised questions regarding population immunity among young adults. OBJECTIVE: To assess the seroprevalence of mumps antibodies among young Israeli adults born after 1987 in order to determine evidence based vaccination policy. METHODS: We conducted a seroprevalence study of mumps IgG antibodies among 441 Israeli adults born in 1988-9, based on a representative sample of sera collected upon recruitment to mandatory military service in 2007. RESULTS: The overall seroprevalence of IgG antibody to mumps virus among 1988-9 born was 83.7%, 82.1% among males and 85.7% among females. Seroprevalence among 2007 recruits was similar to 1999 recruits (83.3%, P=0.89) and significantly lower than 1987 recruits (94.1%, P<0.0001). The absolute decrease between 2007 and 1987 for males was 13.1% (P<0.0001) and for females 7.0% (P=0.02). Seroprevalence was not significantly higher among native Israelis (84.9%) than among young adults born in the Commonwealth of Independent States (81.1%, P=0.46) and significantly higher compared to young adults born in Western Europe or North America (68.2%, P=0.045). CONCLUSIONS: Our findings indicate sub-optimal population seroprevalence despite a 2-dose universal childhood vaccination policy. This study allows better understanding of current mumps outbreaks in Israel and elsewhere following periods of low circulation of wild virus. These findings support mumps vaccination, even for populations and individuals that received two doses during childhood, as means for outbreak containment among young adults, especially in crowded settings, and serve as a reminder to the need for dynamic vaccination policy, supported by health promotion activities.