Community Incidence of Norovirus-associated Infectious Intestinal Disease in England: Improved Estimates Using Viral Load for Norovirus Diagnosis

摘要

Existing estimates of the incidence of infectious intestinal disease (IID) caused by norovirus are based onelectron microscopy or reverse transcription-polymerase chain reaction (RT-PCR). Neither method accuratelyrepresents norovirus disease burden: Electron microscopy has poor diagnostic sensitivity, and RT-PCR has poordiagnostic specificity. In this study, viral load measurements were used to identify cases of norovirus-associatedIID and to produce new incidence estimates for England. IID cases were ascertained in the Study of InfectiousIntestinal Disease in England (1993–1996), and stool specimens were tested by semiquantitative real-time RTPCRfor norovirus. The age-adjusted community incidence of norovirus-associated IID was 4.5/100 person-years(95% credibility interval: 3.8, 5.2), equating to 2 million episodes/year. Among children aged less than 5 years, thecommunity incidence was 21.4/100 person-years (95% credibility interval: 15.9, 27.7), and the incidence of consultationsto general practitioners for norovirus-associated IID was 3.2/100 person-years (95% credibility interval:2.6, 3.8), with 100,000 children visiting their general practitioner for norovirus-associated IID each year. Norovirusis the most common cause of IID in the community in England and is responsible for a similar number of pediatricprimary care consultations as rotavirus.