Wiebke Hellenbrand

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.

Pandemic influenza A(H1N1) 2009 breakthrough infections and estimates of vaccine effectiveness in Germany 2009-2010.

During the 2009 influenza pandemic, a monovalent AS03-adjuvanted vaccine was almost exclusively used in Germany for immunisation against the 2009 pandemic influenza A(H1N1) virus. One-dose vaccination was recommended for all age groups. We applied the screening method for the rapid assessment of vaccine effectiveness (VE) based on reported data of vaccinated and unvaccinated pandemic influenza cases and vaccination coverage estimates. Preliminary results demonstrate excellent VE in persons aged 14-59 years (96.8%; 95% confidence interval (CI): 95.2-97.9) and moderately high VE in those 60 years or older (83.3%; 95% CI: 71.0-90.5).

Further efforts needed to achieve measles elimination in Germany: results of an outbreak investigation

OBJECTIVE To determine morbidity and costs related to a large measles outbreak in Germany and to identify ways to improve the countrys national measles elimination strategy. METHODS We investigated a large outbreak of measles in the federal state of North Rhine-Westphalia (NRW) that occurred in 2006 after 2 years of low measles incidence (< 1 case per 100,000). WHOs clinical case definition was used, and surveillance data from 2006 and 2001 were compared. All cases notified in Duisburg, the most severely affected city, were contacted and interviewed or sent a questionnaire. Health-care provider costs were calculated using information on complications, hospitalization and physician consultations. FINDINGS In NRW, 1749 cases were notified over a 48-week period. Compared with 2001, the distribution of cases shifted to older age groups (especially the 10-14 year group). Most cases (n = 614) occurred in Duisburg. Of these, 81% were interviewed; 15% were hospitalized and two died. Of the 464 for whom information was available, 80% were reported as unvaccinated. Common reasons for non-vaccination were parents either forgetting (36%) or rejecting (28%) vaccination. The average cost per measles case was estimated at 373 euros. CONCLUSION An accumulation of non-immune individuals led to this outbreak. The shift in age distribution has implications for the effectiveness of measles control and the elimination strategy in place. Immediate nationwide school-based catch-up vaccination campaigns targeting older age groups are needed to close critical immunity gaps. Otherwise, the elimination of measles in Germany and thus in Europe by 2010 will not be feasible.

Pneumococcal vaccination policy in Europe.

Infection due to Streptococcus pneumoniae (Pneumococcus) (Pnc) is an important cause of invasive clinical manifestations such as meningitis, septicaemia and pneumonia, particularly in young children and the elderly. A 23-valent polysaccharide Pnc vaccine (PPV) has been available for many years and a 7-valent conjugate Pnc vaccine (PCV) has been licensed since 2001 in Europe. As part of a European Union (EU) funded project on pneumococcal disease (Pnc-EURO), a questionnaire was distributed to all 15 EU member states, Switzerland, Norway and the 10 accession countries in 2003 to ascertain current pneumococcal vaccination policy. Twenty three of the 27 target countries, constituting the current European Union (plus Norway and Switzerland), completed the questionnaire. PPV was licensed in 22 of the 23 responding countries and was in the official recommendations of 21. In all the 20/21 countries for which information was available, risk groups at higher risk of infection were targeted. The number of risk groups targeted ranged from one to 12. At least 17 countries recommend that PPV be administered to all those >65 years of age (in three countries, to those over 60 years of age). Thirteen countries had developed national recommendations for PCV in 2003. No country recommended mass infant immunisation at that time, but rather targeted specific risk groups (between 1 and 11), particularly children with asplenia (n=13) and HIV infection (n=12). PCV use was restricted to children under two years of age in seven countries, and in four countries to children under five years of age. Future decisions on use of pneumococcal vaccines in Europe will be decided on the basis of several factors including: local disease burden; the predicted impact of any universal programme, particularly the importance of serotype replacement and herd immunity (indirect protection to the unvaccinated population); the effectiveness of reduced dose schedules, and vaccine cost. Indeed, at least one country, Luxembourg, has since implemented a universal infant PCV immunisation policy.

Large measles outbreak at a German public school, 2006.

Background: In 2006, a large measles outbreak (n = 614) occurred in Duisburg city, Germany, with 54% of cases aged >9 years. An investigation was launched to determine reasons for the resurgence of measles, assess vaccination coverage and vaccine effectiveness (VE). Methods: A retrospective cohort-study was undertaken at a Duisburg public school affected early in the outbreak. We distributed questionnaires to all 1250 students aged 10–21 years and abstracted vaccination records. Cases were identified according to a standard clinical case definition. Results: Questionnaires were returned by 1098 (88%) students. Vaccination records were abstracted from 859 students, of whom 820 (95.4%) had received at least one, 605 (70.4%) 2, and 39 (4.5%) no dose(s) of measles-containing vaccine (MCV). Coverage with 2 doses was higher in younger students. We identified 53 cases (attack rate = 5%). Measles-virus sequencing revealed genotype D6. After excluding students vaccinated in 2006 and those with a history of measles, the attack rate was 53% in unvaccinated students, 1.0% in students with one, and 0.4% in those with 2 MCV-doses. VE was 98.1% (95% CI: 92–100%) in students with one and 99.4% (95% CI: 97–100%) with 2 MCV-doses. Based on observed attack rates in vaccinated and unvaccinated students with vaccination records and in students without vaccination records, one-dose-coverage among all participating students was estimated at 91%. Conclusions: VE was high. Vaccination coverage was, however, insufficient to prevent the outbreak. Immunization gaps were found especially in older students. To prevent further outbreaks and to achieve the goal of measles elimination in Germany, vaccination coverage must be increased.

The epidemiology of pertussis in Germany: past and present

BackgroundCurrent and past pertussis epidemiology in the two parts of Germany is compared in the context of different histories of vaccination recommendations and coverage to better understand patterns of disease transmission.MethodsAvailable regional pertussis surveillance and vaccination coverage data, supplemented by a literature search for published surveys as well as official national hospital and mortality statistics, were analyzed in the context of respective vaccination recommendations from 1964 onwards.ResultsRoutine childhood pertussis vaccination was recommended in the German Democratic Republic (GDR) from 1964 and in former West German states (FWG) from 1969, but withdrawn from 1974–1991 in FWG. Pertussis incidence declined to <1 case/100.000 inhabitants in GDR prior to reunification in 1991, while in FWG, where pertussis was not notifiable after 1961, incidence was estimated at 160–180 cases/100.000 inhabitants in the 1970s-1980s. Despite recommendations for universal childhood immunization in 1991, vaccination coverage decreased in former East German States (FEG) and increased only slowly in FWG. After introduction of acellular pertussis vaccines in 1995, vaccination coverage increased markedly among younger children, but remains low in adolescents, especially in FWG, despite introduction of a booster vaccination for 9–17 year olds in 2000. Reported pertussis incidence increased in FEG to 39.3 cases/100.000 inhabitants in 2007, with the proportion of adults increasing from 20% in 1995 to 68% in 2007. From 2004–2007, incidence was highest among 5–14 year-old children, with a high proportion fully vaccinated according to official recommendations, which did not include a preschool booster until 2006. Hospital discharge statistics revealed a ~2-fold higher pertussis morbidity among infants in FWG than FEG.ConclusionThe shift in pertussis morbidity to older age groups observed in FEG is similar to reports from other countries with longstanding vaccination programs and suggests that additional booster vaccination may be necessary beyond adolescence. The high proportion of fully vaccinated cases in older children in FEG suggests waning immunity 5–10 years after primary immunisation in infancy. The higher incidence of pertussis hospitalisations in infants suggests a stronger force of infection in FWG than FEG. Nationwide pertussis reporting is required for better evaluation of transmission patterns and vaccination policy in both parts of Germany.

Spatiotemporal Analysis of Invasive Meningococcal Disease, Germany

Meningococcal disease clustering was found by DNA sequence–based finetyping and cluster detection software.

A comparison of hepatitis B seroepidemiology in ten European countries

To inform current and future vaccination strategies, we describe the seroepidemiology of hepatitis B virus (HBV) infection in ten representative European countries using standardized serology that allowed international comparisons. Between 1996 and 2003, national serum banks were compiled by collecting residual sera or by community sampling; sera were then tested by each country using its preferred enzyme immunoassays and testing algorithm, and assay results were standardized. Information on current and past HBV vaccination programmes in each country was also collected. Of the ten countries, six reported low levels (<3%) of antibodies against HBV core antigen (anti-HBc). Of the eight countries testing for HBV surface antigen (HBsAg), the highest prevalence was reported in Romania (5.6%) and in the remaining seven countries prevalence was <1%. Universal HBV vaccination programmes had been established in seven countries as recommended by the World Health Organization, but the seroprevalence of antibodies against HBsAg (anti-HBs) was lower than the reported vaccine coverage in three countries. Regular serological surveys to ascertain HBV status within a population, such as reported here, provide important data to assess the need for and to evaluate universal HBV vaccination programmes.

Pneumococcal disease surveillance in Europe

Pneumococcal disease (Pnc) is responsible for invasive pneumococcal disease (IPD) - mainly meningitis and septicaemia - and is an infection of public health importance in Europe. Following the licensure of an effective conjugate vaccine (PCV) in Europe, several European countries, including France, Germany, the Netherlands, Norway, Spain and the United Kingdom, are introducing universal Pnc childhood immunisation programmes. As part of a European Union (EU) funded project on pneumococcal disease (Pnc-EURO), a questionnaire was distributed in late 2003 to each of the current 25 European Union member states as well as Norway and Switzerland to get a clearer picture of national surveillance for invasive pneumococcal disease (IPD) in Europe. All respondents were contacted in 2006 and asked to provide an update to the questionnaire. Twenty two of the 27 countries targeted completed and returned the questionnaire. Four of the 22 responding countries have no reporting requirement for IPD. Eighteen countries reported a total of 27 national surveillance systems. Case definitions employed in these systems differed. Fourteen of the 18 countries reported collection of IPD strains to a single reference lab for serotyping and in 12 countries to a single laboratory for susceptibility testing. Thirteen countries undertook laboratory quality assurance. Information on age and sex were widely collected, but only 11/27 systems collected information on pneumococcal polysaccharide vaccine status, while 5/27 systems collected information on pneumococcal conjugate vaccine status. The incidence of IPD reported in each of the 18 countries ranged from 0.4 to 20/100 000 in the general population, with a total of 23 470 IPD cases reported over a 12 month period. Surveillance for IPD in Europe is very heterogeneous. Several countries lack surveillance systems. Large differences in reported disease incidence may reflect both true differences, and also variations in patient and healthcare factors, including surveillance. If IPD surveillance in Europe can be strengthened, countries will be able to make informed decisions regarding the introduction of new pneumococcal vaccines and also to monitor and compare the impact and effectiveness of new programmes.

Progress toward Measles Elimination in Germany

While the former East Germany (FEG) achieved a reduction of measles incidence to <1 case per 100,000 population before reunification in 1990, the former West Germany (FWG) experienced significant measles morbidity. In 2001, according to statutory surveillance data, the incidence of measles was still higher in FWG than in FEG (8.7 vs. 0.7 cases/100,000 population). This article describes the development of the vaccination strategies in FEG and FWG, vaccination coverage, results of seroprevalence studies, measles surveillance in Germany, the epidemiology of a recent outbreak, and the role of laboratory diagnosis for measles control in Germany. Recent establishment of comprehensive nationwide surveillance and prevention programs to attain higher vaccine coverage have led to a decrease in measles incidence. However, further improvement of age-appropriate vaccine coverage and closure of immunity gaps in school-age children are necessary to eliminate measles in Germany.