Mumps outbreak in Israel's highly vaccinated society: are two doses enough?

Hebrew University of Jerusalem, Yerushalayim, Jerusalem, Israel
Epidemiology and Infection (Impact Factor: 2.49). 04/2011; 140(3):439-46. DOI: 10.1017/S095026881100063X
Source: PubMed

ABSTRACT Mumps outbreaks in recent years have given rise to questions about the effectiveness of the mumps vaccine. This study examined the epidemiological data from a recent mumps outbreak in Israel and from outbreaks in other countries with high vaccination coverage, and considered whether long-established vaccination policies designed to protect against mumps are in need of revision. Of over 5000 case patients in the Israeli outbreak, half of whom were in the Jerusalem health district, nearly 40% were aged ≥15 years and, of those whose vaccination status was known, 78% had been fully vaccinated for their age - features similar to those in recent mumps outbreaks in Europe and North America. The epidemiological and laboratory evidence suggests that many previously vaccinated adolescents and young adults are now susceptible to mumps because their vaccine-based immunity has waned. Booster vaccination programmes for those at high risk of infection during mumps outbreaks - particularly those in congregate living environments - merit priority consideration.

Download full-text


Available from: Itamar Grotto, Feb 07, 2015
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Even among vaccinated cohorts, prevention and control of mumps outbreaks remain a challenge, owing to sub-optimal population immunity. This is especially true in confined settings, where a single case could be the index for an imminent outbreak. Efficacy of post-exposure prophylaxis has not been demonstrated, while early identification of mumps and comprehensive vaccination of populations in confined settings during outbreaks may enable containment of mumps and disrupt further spread. However, we are not aware of official international guidelines concerning vaccination of exposed individuals during an outbreak, especially in a confined setting. In this article we present our experience with mumps containment during outbreaks through vaccination campaigns in the Israeli civilian and military populations and discuss lessons for containment efforts in other settings. Our analysis shows that a comprehensive ring vaccination should be considered in any case of mumps in confined settings.
    Human vaccines 12/2011; 7(12):1389-93. DOI:10.4161/hv.7.12.18111 · 3.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND:: Despite high two-dose measles-mumps-rubella (MMR) vaccine coverage, a large mumps outbreak occurred on the U.S. Territory of Guam during 2009-2010, primarily in school-aged children. METHODS:: We implemented active surveillance in April 2010 during the outbreak peak and characterized the outbreak epidemiology. We administered third doses of MMR vaccine to eligible students aged 9-14 years in 7 schools with the highest attack rates (ARs) between 5/18/2010-5/21/2010. Baseline surveys, follow-up surveys, and case-reports were used to determine mumps vaccine ARs. Adverse events post-vaccination were monitored. RESULTS:: Between 12/1/2009-12/31/2010, 505 mumps cases were reported. Self-reported Pohnpeians and Chuukese had the highest relative risks (54.7 and 19.7, respectively) and highest crowding indices (mean: 3.1 and 3.0 persons/bedroom, respectively). Among 287 (57%) school-aged case-patients, 270 (93%) had ≥2 MMR doses. A third MMR dose was administered to 1068 (33%) eligible students. Three-dose vaccinated students had an AR of 0.9/1000 compared with 2.4/1000 among students vaccinated with ≤2 doses more than1 incubation period pos-intervention, but the difference was not significant (p= 0.67). No serious adverse events were reported. CONCLUSIONS:: This mumps outbreak occurred in a highly vaccinated population. The highest ARs occurred in ethnic minority populations with the highest household crowding indices. After the third dose MMR intervention in highly affected schools, three-dose recipients had an AR 60% lower than students with ≤2 doses, but the difference was not statistically significant and the intervention occurred after the outbreak peaked. This outbreak may have persisted due to crowding at home and high student contact rates.
    The Pediatric Infectious Disease Journal 10/2012; 32(4). DOI:10.1097/INF.0b013e318279f593 · 3.14 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: By 2005, vaccination had reduced the annual incidence of mumps in the United States by more than 99%, with few outbreaks reported. However, in 2006, a large outbreak occurred among highly vaccinated populations in the United States, and similar outbreaks have been reported worldwide. The outbreak described in this report occurred among U.S. Orthodox Jewish communities during 2009 and 2010. Cases of salivary-gland swelling and other symptoms clinically compatible with mumps were investigated, and demographic, clinical, laboratory, and vaccination data were evaluated. From June 28, 2009, through June 27, 2010, a total of 3502 outbreak-related cases of mumps were reported in New York City, two upstate New York counties, and one New Jersey county. Of the 1648 cases for which clinical specimens were available, 50% were laboratory-confirmed. Orthodox Jewish persons accounted for 97% of case patients. Adolescents 13 to 17 years of age (27% of all patients) and males (78% of patients in that age group) were disproportionately affected. Among case patients 13 to 17 years of age with documented vaccination status, 89% had previously received two doses of a mumps-containing vaccine, and 8% had received one dose. Transmission was focused within Jewish schools for boys, where students spend many hours daily in intense, face-to-face interaction. Orchitis was the most common complication (120 cases, 7% of male patients ≥12 years of age), with rates significantly higher among unvaccinated persons than among persons who had received two doses of vaccine. The epidemiologic features of this outbreak suggest that intense exposures, particularly among boys in schools, facilitated transmission and overcame vaccine-induced protection in these patients. High rates of two-dose coverage reduced the severity of the disease and the transmission to persons in settings of less intense exposure.
    New England Journal of Medicine 11/2012; 367(18):1704-13. DOI:10.1056/NEJMoa1202865 · 54.42 Impact Factor