title: Re-assessing the total burden of norovirus circulating in the United Kingdom population.
abstract: The second Infectious Intestinal Diseases study (IID2) estimated the incidence of norovirus in the UK at 47/1000 population (three million cases annually). Clinically significant norovirus was defined using a cycle threshold (ct) value of <30; a more stringent cut-off than used in diagnostic laboratories. The low infectious dose of norovirus means asymptomatic individuals potentially contribute to ongoing transmission. Using a less stringent but diagnostically relevant threshold increases the estimation of the population burden of norovirus infection by around 26% to 59/1000 person years (95% CI 52.32-64.98), equating to 3.7 million norovirus infections annually (3.3-4.1 million). With possible vaccines on the horizon for norovirus, having a good estimate of the total burden of norovirus infection, as well as symptomatic disease will be useful in helping to guide vaccination policy when candidate vaccines become available.
authors.affiliation: National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Gastrointestinal Infections at the University of Liverpool, Liverpool, UK. Electronic address: john.harris@liverpool.ac.uk.
authors.forename: John P
authors.initials: JP
authors.lastname: Harris
authors.affiliation: National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Gastrointestinal Infections at the University of Liverpool, Liverpool, UK.
authors.forename: Miren
authors.initials: M
authors.lastname: Iturriza-Gomara
authors.affiliation: National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Gastrointestinal Infections at the University of Liverpool, Liverpool, UK.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: O'Brien
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission / Q000821:virology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D029322:Norovirus / Q000472:pathogenicity / Q000502:physiology*; D006113:United Kingdom / Q000453:epidemiology; D014765:Viral Vaccines / Q000096:biosynthesis
chemical_list: D014765:Viral Vaccines
keywords: Calicivirus; Gastrointestinal infections; Infectious diseases; Norovirus