Seroepidemiology of mumps in Europe (1996-2008): why do outbreaks occur in highly vaccinated populations?

Abstract

Mumps outbreaks have recently been recorded in a number of highly vaccinated populations. We related seroprevalence, epidemiological and vaccination data from 18 European countries participating in The European Sero-Epidemiology Network (ESEN) to their risk of mumps outbreaks in order to inform vaccination strategies. Samples from national population serum banks were collected, tested for mumps IgG antibodies and standardized for international comparisons. A comparative analysis between countries was undertaken using age-specific mumps seroprevalence data and information on reported mumps incidence, vaccine strains, vaccination programmes and vaccine coverage 5-12 years after sera collection. Mean geometric mumps antibody titres were lower in mumps outbreak countries [odds ratio (OR) 0·09, 95% confidence interval (CI) 0·01-0·71)]. MMR1 vaccine coverage ⩾95% remained protective in a multivariable model (P < 0·001), as did an interval of 4-8 years between doses (OR 0·08, 95% CI 0·01-0·85). Preventing outbreaks and controlling mumps probably requires several elements, including high-coverage vaccination programmes with MMR vaccine with 4-8 years between doses.

Fig. 1

[colour online]. Mumps incidence in Romania in 2002 compared to mumps antibody seroprevalence. Mumps vaccination was started in 2004.

Fig. 2

[colour online]. Mumps incidence in the UK in 2005 by age group compared to mumps vaccination status and mumps antibody seroprevalence (MMR2 was introduced in 1995 but coverage measurements started in 1999).

Fig. 3

[colour online]. Mumps incidence in Bulgaria in 2008 by age group compared to mumps vaccination status and mumps antibody seroprevalence.

Fig. 4

[colour online]. Mumps incidence in Hungary in 2007 by age group compared to mumps vaccination status and mumps antibody seroprevalence.

Fig. 5

[colour online]. Mumps incidence in Slovakia in 2006 by age group compared to mumps vaccination status and mumps antibody seroprevalence.

Fig. 6

[colour online]. Mumps incidence in the Czech Republic in 2006 by age group compared to mumps vaccination status and mumps antibody seroprevalence.

Fig. 7

[colour online]. Mumps incidence in Spain in 2007 by age group compared to mumps vaccination status and mumps antibody seroprevalence (MMR2 was introduced in 1996 for persons aged 11–13 years, but was given to children aged 3-6 years from 2000).