Encyclopedia
The concept of the Disability Adjusted Life Year (DALY) is a composite measure of years of life lost and years lived with disability. One DALY is the equivalent of a year of healthy life lost if a person had not experienced disease. Norovirus is the commonest cause of gastrointestinal diseases worldwide, the levels of disease activity varies from one season to the next for reasons not fully explained. Infection with norovirus is generally not severe, and is normally characterised as mild and self-limiting with no long term sequelae. In this study we modelled a range of estimates of DALYs, for community cases of norovirus in England and Wales. We estimated a range of DALYs for norovirus to account for mixing of severity of disease and the range of length of illness experienced by infected people. Our estimates were between 1159 and 4283 DALYs per year, or 0.3 to 1.2 years of healthy life lost per thousand cases of norovirus. These estimates provide evidence that norovirus leads to a considerable level of ill health in England and Wales. This information will be helpful should candidate norovirus vaccines become available in the future.
- norovirus
- gastrointestinal diseases
- calicivirus
1. Introduction
Understanding the burden of disease is an important step towards developing policies aimed at mitigating or preventing illness. Currently there are candidate vaccines that show promising results in protection against norovirus disease [16-18]. Symptoms of norovirus infections normally last between one and three days [11,12]. However, recent analysys suggest that this can be longer, particularly in the very young (those aged < 5 years) [13]. Norovirus activity varies yearly, some years have increased illness whereas others . Therefore, variation in the severity of illness experienced by those who are ill with norovirus, a single DALY calculation for norovirus is unlikely to be appropriate or a realistic measure of the burden of the disease.
