Eurosurveillance - Volume 12, Issue 12, 01 December 2007

From the time I was appointed as Director of the European Centre for Disease Prevention and Control (ECDC) in 2005, I and the ECDC Governing and Advisory Bodies faced the task of tackling the 46 diseases under mandatory notification in the European Union (EU), as well as severe acute respiratory syndrome (SARS), avian influenza and West Nile virus.

The main objectives of this pilot study were to test the potential use of the disease burden concept in the field of infectious diseases, including data quality and availability; to recommend future studies; and to stimulate a debate. The disease burden of seven infectious diseases (influenza, measles, HIV, campylobacteriosis, infection with enterohaemorrhagic Escherichia coli, salmonellosis and tuberculosis) in Europe was estimated by calculating Disability Adjusted Life Years (DALYs), a composite measure that attempts to combine mortality, incidence and sequelae, taking duration and severity into account. The results show that the relative burden of diseases as measured by DALYs differs from that only measured by incidence or mortality. Several limitations regarding data availability and quality have been identified, resulting in an underestimation of the true burden of disease in this pilot. Notwithstanding these, HIV-infection, tuberculosis (TB) and influenza are estimated to cause the highest burden in Europe among the selected diseases. The burden of foodborne diseases (campylobacteriosis, infection with enterohaemorrhagic Escherichia coli and salmonellosis) and in particular of measles is lower. A consideration of the relative comparison of burden between diseases can be useful when tackling the difficult, sensitive but necessary task of identifying priority actions. A low burden stresses the need for continued support for prevention and control whereas a high burden indicates the need for additional interventions. Following this pilot project, a generalised burden of disease study for infectious diseases in Europe is recommended. Such a study would benefit from an approach that identifies and combines several methods of investigation, including epidemiological modelling, and it should be done in collaboration with other international efforts in this field.

In January 2006, an outbreak of hepatitis A occurred in a socio-economically deprived area of Liverpool, in the United Kingdom (UK), where extensive community outbreaks of hepatitis had previously occurred. A total of nine cases were confirmed. Five of these were linked within a primary school. The outbreak initially occurred among a close social contact group, but there was evidence of subsequent person-to-person transmission within a local primary school. The school was attended by 221 pupils (age range 4-12 years) with a total of 37 teaching and other staff (age range 22-71 years). Following local risk assessment, mass hepatitis A virus (HAV) vaccination was offered to all staff and pupils, as all were judged to be likely to have been in close contact with the affected pupils. A total of 188 of 217 eligible children (87%), and 33 of 37 staff (89%) were vaccinated. A salivary seroprevalence survey was conducted at the same time as vaccination to assess the benefit of this intervention in the school population. The survey confirmed high levels of susceptibility to hepatitis A in this setting (97.8%, 95% CI 91.6 to 99.62). The direct costs of intervention were estimated as £5,000. The cost effectiveness of intervention varies widely (£60.50 to £2,099 per case avoided) depending on the expected attack rate, which is difficult to estimate due to heterogeneity in published studies.

Once a year, every country that participates in the European Surveillance Scheme for Travel Associated Legionnaires' Disease (EWGLINET) is asked to submit a dataset comprising all cases of Legionnaires' disease (not only travel-associated) with date of onset in the previous year. This paper presents the data collected for 2005 and 2006. In this period, 11,980 cases were reported by 35 countries, showing a continued increase compared with earlier years. 214 outbreaks or clusters were reported, involving 1028 cases. 377 cases died, giving a case fatality rate of 6.6%. The highest incidence rates in both years were recorded in Spain, while six countries reported a rate of less than one case per million population in at least one of the years. Incidence rates by age group were included in the dataset for the first time, showing an increase of the overall rate with age. Main method of diagnosis was the urinary antigen test (76.0%), whilst the percentage of cases diagnosed by culture fell from 10.0% in previous years to 8.9% in 2005-2006. .

The ninth international meeting of the European Laboratory Working Group on Diphtheria (ELWGD) and the first annual meeting of the Diphtheria Surveillance Network (DIPNET) was held in Vouliagmeni, Greece, in November 2006. The recognition of DIPNET as an established Dedicated Surveillance Network (DSN) by the European Commission (EC) was announced, with the specific objective ""to establish a Pan-European network of expertise for the prevention of diphtheria and other related infections"". At the meeting, DIPNET participants from the European Union (EU) Member States and associated countries as well as collaborators from countries beyond EU presented the current situation concerning the clinical, epidemiological and microbiological aspects of diphtheria and related infections. Issues highlighted included the need for improving surveillance systems, supporting laboratory diagnostics globally, and undertaking screening and seroepidemiological studies to sustain diphtheria control in the WHO European Region and beyond.

During influenza epidemics, school-aged children are amongst the first affected patients. They frequently then spread the virus within their families. Recognising influenza activity in schools may therefore be an important indicator of early activity in the wider community. During 2005/06, influenza B was associated with high levels of morbidity in school-children and over 600 schools outbreaks were reported to the Health Protection Agency by local Health Protection Units. While it is not possible to directly monitor influenza in schools, the feasibility and validity of using sentinel school absenteeism data, as a proxy for influenza in the community can be investigated. From week 02/07 to 20/07, eight primary and three secondary schools from five HPA regions were able, via the Department of Health-funded Health Protection Informatics website, to report daily electronic registration data, relating to absenteeism due to illness. Aggregated absenteeism data due to illness peaked the same week as indices for the age group comparable to that used by the Royal College for General Practitioners and NHS Direct schemes. When illness-defined absenteeism data was stratified into primary and secondary schools, absence in primary schools peaked one week before that in secondary schools and the established schemes for all ages. The start time of the study meant that initial increases in activity could not be measured. These encouraging results justify expanding this sentinel scheme to collect more rigorous evidence of the usefulness of absenteeism as a proxy for influenza activity and a tool to inform policy and trigger local responses.

In Ireland, influenza and pneumococcal vaccines are recommended for adults aged 65 years and over and for those with chronic illness or immunosuppression. Influenza vaccine is recommended for healthcare workers (HCWs) and residents of long stay care facilities. Influenza vaccine uptake is only available for those aged 65 years and over. We conducted a survey to estimate the size of risk groups between 18 and 64 years of age, influenza and pneumococcal vaccine uptake in this group, and to determine possible factors influencing vaccine uptake to improve targeted immunisation programmes. Among respondents aged 18-64 years, 136 of 1,218 (11%) belonged to a health risk group; uptake of influenza and pneumococcal vaccine in these risk groups was 28% (95% CI: 20.9-35.4) and 11% (95% CI: 6.7-17.2) respectively. Uptake among persons aged over 65 years was 69% (95% CI: 62.2-74.4) and 41% (95% CI: 35.0-47.9) for influenza and pneumococcal vaccine, respectively. Influenza vaccine uptake among HCWs was 20% (95% CI: 13.1-28.7). Half (47.6%) of influenza-vaccinated respondents reported that their family doctor had recommended it; 60% of non-vaccinated respondents, for whom influenza vaccine was indicated, saw themselves at low risk of influenza.

Nuremberg was the third European city to host the European Congress of Virology in September this year (http://www.eurovirology.org). Some 1,500 scientists from Europe and elsewhere came together to share their knowledge on basic and applied research in clinical, veterinary and plant virology. The main focus was on human pathogenic viruses, providing a platform where basic research and clinical application came into contact. The topics covered all areas of research in virology, from basic molecular biology and immunology to epidemiology, vaccine development, and diagnostics. For this meeting report, the Editorial team has selected some of our highlights out of the many excellent keynote lectures and workshop contributions.