Emergence of New Norovirus Variants on Spring Cruise Ships and Prediction of Winter Epidemics
2008

New Norovirus Variants on Cruise Ships

Sample size: 43 publication Evidence: moderate

Author Information

Author(s): Verhoef Linda, Depoortere Evelyn, Boxman Ingeborg, Duizer Erwin, van Duynhoven Yvonne, Harris John, Johnsen Christina, Kroneman Annelies, Le Guyader Soizick, Lim Wilina, Maunula Leena, Meldal Hege, Ratcliff Rod, Reuter Gábor, Schreier Eckart, Siebenga Joukje, Vainio Kirsti, Varela Carmen, Vennema Harry, Koopmans Marion

Primary Institution: National Institute for Public Health and the Environment

Hypothesis

Are new norovirus variants emerging on cruise ships and how can we predict winter epidemics?

Conclusion

The emergence of new norovirus variants on cruise ships is linked to increased outbreaks in the community, suggesting a need for an early warning reporting system.

Supporting Evidence

  • 43 outbreaks were reported from 13 vessels during the study period.
  • The overall attack rates varied from <1% to 41%, with the highest rates for passengers at 48%.
  • A significant correlation was found between off-season outbreaks and subsequent seasonal outbreaks.

Takeaway

Norovirus can spread easily on cruise ships, and new types of the virus can lead to more sickness in the winter. We need a better way to track these outbreaks.

Methodology

Epidemiologic, virologic, and baseline data were collected from various sources including health authorities and laboratories.

Potential Biases

Reporting bias may have occurred due to media attention and the nature of outbreak investigations.

Limitations

Data collection was incomplete and delayed, which may have affected the analysis of outbreaks.

Participant Demographics

Outbreaks occurred on cruise ships with passengers and crew, but specific demographics were not detailed.

Statistical Information

P-Value

p<0.001

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.3201/eid1402.061567

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