Clin Infect Dis. 2012 Apr 4. [Epub ahead of print]
Severe outcomes are associated with genogroup 2 genotype 4 norovirus outbreaks: A systematic literature review.
Desai R, Hembree CD, Handel A, Matthews JE, Dickey BW, McDonald S, Hall AJ, Parashar UD, Leon JS, Lopman B.
SourceEpidemic Intelligence Service Officer, Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
AbstractBackgroundNoroviruses are the most common cause of epidemic gastroenteritis, however, the relative impact of individual factors underlying severe illness are poorly understood. This report reviews published norovirus outbreak reports to quantify hospitalization and mortality rates and assess their relationship with outbreak setting, transmission route, and strain.MethodsBetween January 1993 and June 2011, 2435 non-duplicate articles were identified in PubMed, EMBASE, and Web of Knowledge using a string of terms related to "norovirus" and "outbreak". Inclusion criteria included outbreaks with a minimum of two ill persons with a common exposure and at least one RT-PCR-confirmed case of norovirus disease. Univariate analyses were performed and multivariable models were fitted to estimate the independent effect of each factor.Results843 norovirus outbreaks reported in 233 published articles from 45 countries were analyzed. Based upon 71,724 illnesses, 501 hospitalizations, and 45 deaths, overall hospitalization and mortality rates were 0.54% and 0.06%, respectively. In multivariate analysis, genogroup II genotype 4 (GII.4) norovirus strains were associated with higher hospitalization (IRR: 9.4, 95% CI: 6.1 - 14.4, p < 0.001) and mortality rates (IRR: 3.1, 95% CI: 1.3 - 7.6, p=0.013); deaths were much more likely to occur in outbreaks occurring in healthcare facilities (IRR: 60, 95% CI: 6 - 109, p=0.013).ConclusionsOur review suggests that hospitalizations and deaths were more likely in outbreaks associated with GII.4 viruses, independent of other factors, and underscores the importance of developing vaccines against GII.4 viruses to prevent severe disease outcomes.
- [PubMed - as supplied by publisher]