The burden of 2009 pandemic influenza A(H1N1) in the Netherlands.

BACKGROUND: The disease burden of the 2009 influenza pandemic has been debated but reliable estimates are lacking. To guide future policy and control, these estimates are necessary. This study uses burden of disease measurements to assess the contribution of the pandemic influenza A(H1N1) virus to the overall burden of disease in the Netherlands. METHODS: The burden of disease caused by 2009 pandemic influenza was estimated by calculating Disability Adjusted Life Years (DALY), a composite measure that combines incidence, sequelae and mortality associated with a disease, taking duration and severity into account. Available influenza surveillance data sources (primary care sentinel surveillance, notification data on hospitalizations and deaths and death registries) were used. Besides a baseline scenario, five alternative scenarios were used to assess effects of changing values of input parameters. RESULTS: The baseline scenario showed a loss of 5800 DALY for the Netherlands (35 DALY per 100 000 population). This corresponds to 0.13% of the estimated annual disease burden in the Netherlands and is comparable to the estimated disease burden of seasonal influenza, despite a different age distribution in incidence and mortality of the pandemic compared to seasonal influenza. CONCLUSIONS: This disease burden estimate confirmed that, although there was a higher mortality observed among young people, the 2009 pandemic was overall a mild influenza epidemic. The disease burden of this pandemic was comparable to the burden of seasonal influenza in the Netherlands.

[Effects of ageing on infectious disease]. / Effecten van vergrijzing op infectieziekten.

Expectations are that 25% of the Dutch population will be aged 65 years or older in 2050 whilst in 2008 this proportion was only 15%. As a consequence the annual absolute number of new cases of specific infectious diseases will increase. Elderly people often have less clear symptoms of infection, making it harder for clinicians to recognize the disease. Morbidity and mortality caused by infections increase with age. Ageing will possibly cause an increase in levels of antibiotic resistance. There will be more elderly people in hospitals and nursing homes, where more antibiotics are used. This development will come in addition to other developments in the field of antibiotic resistance. There will be more elderly people with chronic HIV and viral hepatitis B and C infection and their complications because patients who are presently infected with those pathogens are ageing. Policy makers should more often consider introducing vaccination of older age groups against certain infectious diseases.

The burden of infectious diseases in Europe: a pilot study.

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.