2153. Impact of Norovirus Testing Changes on Hospital-Acquired Norovirus Infections

BACKGROUND: Norovirus is highly contagious and can spread rapidly through healthcare facilities. Controlling transmission of norovirus infections can be challenging. Early diagnosis allows for infection prevention measures to be implemented in a timely manner. The objective of this study was to determine the effect of decreasing barriers to norovirus testing on hospital-acquired (HA) cases. METHODS: A before-after study was conducted evaluating the impact of increasing the availability of norovirus testing on HA infections. From January 1, 2012 to October 16, 2017, all norovirus tests required the approval from the laboratory medicine resident, and testing was performed once a day. A polymerase chain reaction (PCR) system that required a two-step process was used. On October 17, 2017, the laboratory began using a PCR that performs testing in one step, allowing the laboratory to perform testing more frequently. Approval of the laboratory medicine resident was no longer required. HA norovirus rates and percent of positive test pre and post-implementation were compared using chi-square analysis. HA cases were defined as patients admitted without signs or symptoms of norovirus infection on inpatient units. A Mann–Whitney U test was used to compare the average of HA infections per cluster pre and post-implementation. A cluster was defined as two or more associated cases. No other infection prevention interventions were implemented during this time frame. RESULTS: After implementation of the new testing methodology, there was no difference in percent of positive norovirus test between the study periods [9.4% (46/487) pre-implementation vs. 6.9% (11/160) post-implementation, P = 0.16]. The proportion of norovirus infections that were HA increased slightly after implementation [37% (17/46) pre-implementation vs. 55% (6/11) post-implementation, P = 0.16]. There was no difference in HA norovirus infections associated with a cluster between the study periods [3.6 cases/cluster pre-intervention vs. 2.5 cases/cluster post-intervention, P = 0.86) CONCLUSION: There was no significant difference in the number of HA norovirus cases with improved testing availability. A limitation to this study is the short length of the post-implementation evaluation period compared with the pre-implementation period. DISCLOSURES: All authors: No reported disclosures.