Mumps Outbreaks in Vaccinated Population

Abstract

Abstract

The available approved safe and effective vaccines have prevented millions of deaths. When compared to prevaccine era, more than 98% decrease has been recorded for many diseases like diphtheria, invasive Haemophilus influenzae, measles, rubella, rotavirus, and hepatitis A. Further, the successful global eradication of small pox and near-elimination of polio from most of the global regions underlines the importance of vaccination. The available literature on mumps reveals that it is far from eradication. The safe and effective measles–mumps–rubella (MMR) vaccine contains a strain of mumps virus. The recent mumps outbreaks in vaccinated population again brought focus back on vaccine doses and protective immunity to virus. There was no significant change in number of cases reported over the years. In the last 5 years, a shift in the age-specific incidence of the disease towards higher age has been found. Many of the outbreak investigation studies have indicated incomplete protection by two doses of mumps-containing vaccine and possible waning immunity. The studies on outbreak investigations collectively call for efforts to maintain high two-dose vaccination coverage. Additional vaccine coverage may be considered to reduce large-scale mumps outbreaks. If additional dose is given, its justification, safety and effectiveness is required. Further, a study on mumps virus genotypes, its heterogeneity and immunological aspects is essential. A detailed investigation is required to study the possible antigenic differences between the vaccine strain and outbreak strain.  

Keywords: Mumps, Parotitis, MMR vaccine, Outbreak, Vaccine preventable disease