Norovirus outbreaks on college and university campuses

Abstract

Objective: To describe norovirus outbreaks at colleges and universities. Participants: None. Conducted September 2016 to March 2018. Methods: College and university norovirus outbreaks reported to the US National Outbreak Reporting System (NORS, 2009-2016) or published and indexed by EMBASE, PubMed, and Web of Science (1985-2017) were analyzed. Results: Seventy-seven norovirus outbreaks were reported to NORS and 23 were identified in the systematic literature review. Outbreaks occurred more frequently during the beginning of the school year (September-February). NORS outbreaks were more often spread by person-to-person transmission (61%) and, in published outbreaks, by food (57%). The reported exposures of published outbreaks were campus dining (n = 8) and ill food service workers (n = 7). Higher attack rates were associated with smaller on-campus population size, social networks or residences, and specific food exposures. Common control measures were communal area disinfection and health/hygiene education. Conclusions: Recommendations summarized to prevent and control norovirus outbreaks at colleges or universities.

Keywords: Control; norovirus; outbreak; prevention; students; systematic review.

Figure 1:

Count of United States college and university outbreaks reported to the National Outbreak Reporting System (n=77) and identified from a systematic literature review (n=14, two additional US-based outbreaks were reported as “Southeast” and “Mid-Atlantic” and so could not be assigned to a state), 1980-2016. Please see Methods for detail

Figure 2:

Monthly distribution of college and university outbreaks by primary mode of transmission reported to the National Outbreak Reporting System (NORS; A, n=77) and identified from a systematic literature review (B, n=16), 1980-2016.

Figure 3.

Distribution of symptom frequencies among college and university norovirus outbreaks reported to the National Outbreak Reporting System (NORS; A, n=77) and identified from a systematic literature review (B; n=23). Bars represent box and whiskers plot of frequency of each symptom across different college and university outbreaks, showing lower bound value, first quartile, median, third quartile, and upper bound value. Number of outbreaks reporting symptom frequencies are indicated below each symptom and differ because not all outbreaks listed the frequency of each symptom.

Figure 4:

23 outbreaks matching the eligibility criteria were included in the systematic review following a review of titles, abstracts, and full-length articles identified by the search string. The flow diagram shows the process of arriving at these 23 outbreaks, with each row showing a different step of review and elimination of articles not matching eligibility criteria. Two independent reviewers were involved in each step of the process, with a third reviewer available to resolve discrepancies.

Figure 5:

Summary of existing key norovirus outbreak control and prevention recommendations for college and universities^,,-51.