Long-term care facilities face high burden of norovirus outbreaks
Long-term care facilities in the United States have a high burden of norovirus outbreaks, which result in a significant number of deaths and hospitalizations, according to CDC surveillance data.
“Norovirus is the most common gastroenteric disease in the U.S., causing around 20 million illnesses nationwide each year. We know from previous studies that outbreaks of acute gastroenteritis caused by norovirus are common in long-term care facilities,” Sara Mirza, PhD, MPH, an epidemiologist in CDC’s Division of Viral Diseases, told Healio.
“We wanted to describe and quantify this issue across the U.S. using the most comprehensive and long-standing surveillance platforms available for domestic norovirus outbreaks,” Mirza said.
Mirza and colleagues used CDC-collected data on norovirus outbreaks in the National Outbreak Reporting System and CaliciNet to assess outbreaks in nursing homes, assisted living facilities and other long-term care facilities occurring between 2009 and 2018.
Overall, 13,092 outbreaks and 416,284 outbreak-associated cases of norovirus were reported. According to Mirza and colleagues, the number of outbreaks increased throughout the years but stabilized at 4.1 outbreaks per 100 long-term care facilities annually since 2014.
They found that the outbreaks were primarily spread via person-to-person transmission, with 75% occurring between December and March. GII.4 Sydney was the most dominant strain among outbreaks with available typing data.
For every 1,000 cases, there were 21.6 hospitalizations and 2.3 deaths, with long-term care facility residents having higher attack rates than staff (29% vs. 10.9%; P < .001), the researchers found.
“Long-term care facilities should implement plans to prevent norovirus outbreaks spread through person-to-person contact, especially since residents of long-term care facilities are particularly vulnerable to norovirus complications requiring medical support,” Mirza said. “Outbreak surveillance can inform development of interventions for this vulnerable population, such as vaccines targeting GII.4 norovirus strains.”