Pennsylvania long-term care (LTC) facilities report gastrointestinal (GI) infections, including norovirus, to the Pennsylvania Patient Safety Authority through its Pennsylvania Patient Safety Reporting System. In April 2014, in accord with changes to national standards, the Authority revised the LTC criteria for identifying and reporting gastroenteritis. The revision included a new gastroenteritis subcategory that allows detailed surveillance and reporting of norovirus cases separate from other causes of gastroenteritis within PA-PSRS.
Norovirus events comprised the majority of GI infections for 12 of 36 months in three clusters of consecutive months concurrent with what is commonly considered the norovirus season (Figure 2). These three clusters accounted for 87.5% of all norovirus reports over the three-year period.
Also of note are the seasonal spikes of monthly norovirus rates as compared to relatively stable monthly rates of other GI infections (Figure 3).
The timing and magnitude of event clusters varied among facilities, as shown when grouped by Pennsylvania region (Figure 4). Each region had different monthly peaks, demonstrating that although events are seasonal, variability exists by region. Table 1 shows peak norovirus periods and rates for the Authority's six state regions.
|Region||Peak Month and AY||Peak Rate*||Average Rate, AY15–AY17*|
Note: Academic years are for the 12 months ended June 30 of each year.
AY, Academic year.
* Rate calculated by number of norovirus reports per 1,000 resident days.
Excerpted from: Bradley S, Finley E. Combat norovirus infections in long-term care facilities. Pa Patient Saf Advis 2018 Jun;15(2). http://patientsafety.pa.gov/ADVISORIES/Pages/201806_NorovirusUpdate.aspx.