Risks of the European Reduction Program Incidence of Epidemic Parotitis Delayed Implementation in Russian Federation of WHO European Region

Abstract

Analyzing mumps incidence worldwide, we revealed that all European countries are endemic to this viral infection. In the Russian Federation Epidemic Parotitis (EP) was taken under control since 1981, when mass pediatric vaccination has begun, followed by introduction in 1998 of children’s revaccination at the age of 6. During four decades the EP incidence in Russia has decreased 300-400 times, mortality and a number of residual phenomena have been eliminated. In 2002 the WHO Regional Committee has adopted a program to eliminate measles, reduce congenital rubella syndrome to 0.01 per 1 000 live births and the EP incidence to 1.0 or less per 100 000 population by 2010. For eighteen years the program has been delayed several times and still has not reached its goals. The main goal of our study was to evaluate humoral immunity in EP in patient cohorts of different age. We also detected specific immunoglobulin levels and dynamics in people from 3 mumps foci; identified objective causes interfering the epidemiological well-being of the Russian population, despite vaccination coverage of 95-96%. Our observations identified 2 risk groups with high mumps probability: subjects in age groups of 20 – 29 and 30 – 39 years old. The study demonstrated that the efficacy of vaccination, the intensity and duration of neutralizing mumps antibody retention is related directly to the personal immunological status and vaccine quality. In addition, our observations of subjects from 3 mumps foci as well as those, who we studied in our laboratory directly during the sporadic EP incidence increase, showed that stable, strong herd immunity cannot be achieved in long term only through pediatric vaccination and revaccination even with high population coverage. There always will be subjects non immune to EP. This number will grow after a certain time and result in an outbreak. The global goal is to monitor herd immunity both in Europe as a whole and in certain territories, including Russia. The main reason that the European community has not been able to reduce the EP incidence to goal point is the absence of a single international antibody standard that will allow to compare the individual defense level with the amount actually necessary for the protection, detected by standardized anti-mumps IgG test-system. We hope WHO will hear us and under its auspices a single certified international serum standard with known antibody level in IU will be created, and make real EP protection potential assessment possible.