The number of norovirus outbreaks increased in the 2021-2022 surveillance year, returning to similar to pre pandemic levels, according to research published in Morbidity and Mortality Weekly Report. Jan Vinjé, PhD, and colleagues examined norovirus outbreaks and found that, in the 2021-2022 surveillance year, 12 participating states reported 992 outbreaks. In comparison, in 2019-2020 and 2020-2021, the same states reported 1,056 and 343 \ outbreaks, respectively. During the pre-pandemic surveillance years, the number of norovirus outbreaks varied from 1,219 (2015-2016) to 1,471 (2018-2019). The characteristics of norovirus outbreaks reported by participating states from 2021-2022 were similar to those reported during pre-pandemic years. Most outbreaks (82%) were due to person-to person spread and 59% occurred in long-term care facilities. “Non-pharmaceutical interventions implemented during the COVID-19 pandemic were likely effective in preventing outbreaks of other infectious diseases, including norovirus,” Dr. Vinjé and colleagues wrote.
