The comparative sero-epidemiology of varicella zoster virus in 11 countries in the European region.

The European sero-epidemiology network (ESEN2) aims to standardise serological surveillance of varicella zoster virus (VZV) in 11 participant countries. In each country, serum banks were collected between 1996 and 2003 and tested for VZV antibodies. Assay results were standardised so that international comparisons could be made. Age-specific forces of infection were calculated for three age groups (<5, 5-9 and >or=10 years of age) and used to estimate the base reproduction number (R(0)) and the herd immunity threshold (H). Most VZV infection occurred in childhood, but there was a wide variation in transmissibility, with R(0) ranging from 16.9 in the Netherlands to 3.3 in Italy. Herd immunity thresholds varied from 70% in Italy to 94% in the Netherlands. There are substantial differences in VZV sero-epidemiology within the European region, which will need to be taken into account in designing national policies regarding VZV vaccination.

The seroepidemiology of herpes simplex virus type 1 and 2 in Europe.

OBJECTIVES: To describe the seroepidemiology of herpes simplex virus (HSV) types 1 and 2 in the general populations of eight European countries to better understand recent reported changes in disease epidemiology. METHODS: Belgium, Bulgaria, Czech Republic, England and Wales, Finland, Germany, Netherlands, and Slovenia conducted national cross sectional serological surveys for HSV-1 and HSV-2 between 1989 and 2000. Survey sizes ranged from 3000 to 7166 sera. External quality control was ensured through reference panel testing. RESULTS: Large intercountry and intracountry differences in HSV-1 and HSV-2 seroprevalence were observed. Age standardised HSV-1 seroprevalence ranged from 52% in Finland, to 57% in the Netherlands, 67% in Belgium, 81% in Czech Republic, and 84% in Bulgaria. Age standardised (>12 years) HSV-2 seroprevalence ranged from 24% in Bulgaria, to 14% in Germany, 13% in Finland, 11% in Belgium, 9% in Netherlands, 6% in Czech Republic, and 4% in England and Wales. In all countries, probability of seropositivity for both infections increased with age. A large proportion of teenagers and young adults remain HSV-1 susceptible particularly in northern Europe. Women were significantly more likely to be HSV-2 seropositive in six of seven (p<0.05) countries and HSV-1 seropositive in four of seven (p<0.05) countries, particularly in northern Europe. No significant evidence of a protective role of HSV-1 for HSV-2 infection was found adjusting for age and sex (p<0.05). CONCLUSIONS: There is large variation in the seroepidemiology of HSV-1 and HSV-2 across Europe. The observation that a significant proportion of adolescents are now HSV-1 susceptible may have implications for transmission and clinical presentation of HSV-1 and HSV-2.

Etiology of measles- and rubella-like illnesses in measles, mumps, and rubella-vaccinated children.

The viral etiology of measles- or rubella-like illnesses after MMR (measles, mumps, and rubella) vaccination was studied prospectively in 993 acutely ill Finnish children with fever and rash in 1983-1995. Their sera were tested for adeno-, entero-, and parvovirus B19 antibodies. Sera of 300 children <4 years old were also tested for human herpesvirus 6 (HHV-6) antibodies. Measles and rubella had been excluded by previous antibody testing. Serologic diagnosis of adeno-, entero-, or parvovirus infection was based on EIA (IgM or IgG antibodies) and that of HHV-6 on indirect immunofluorescence. A viral etiology was verified in 368 cases, most commonly parvovirus (20%), followed by enterovirus (9%) and adenovirus (4%). Among young children, HHV-6 infection was found in 37 (12%). Thirty-eight children (4%) had double infections. This study confirms that measles- or rubella-like illnesses in MMR-vaccinated children are often caused by other viruses. Each suspected vaccine failure requires laboratory confirmation to maintain reliable surveillance and control and to establish the specific etiology of the disease.