(NEXSTAR) — Outbreaks of norovirus are currently spiking across the country — and somewhat earlier than in previous years.

Health officials say the timing and volume of these outbreaks isn’t entirely unexpected, considering the newest outbreaks coincide with the easing of pandemic restrictions.

“Prevention measures implemented during the COVID-19 pandemic were likely effective in preventing norovirus outbreaks,” Marisa Lubeck, a health communication specialist with the Centers for Disease Control and Prevention, previously told Nexstar. “As pandemic restrictions have relaxed, the number of norovirus outbreaks has returned to levels similar to pre-pandemic years.”

Nevertheless, illnesses caused by norovirus infection can be concerning, especially during outbreaks involving young children, the elderly and those with compromised immune systems.

Perhaps more concerning is the fact that long-term health facilities and hospitals are the most common setting for norovirus outbreaks in the United States, and can originate from any number of sources, including residents, workers, visitors or contaminated foods. Between 2009 and 2013, for instance, 62.7% of all outbreaks reported via the CDC’s National Outbreak Reporting System had taken place in healthcare facilities.

The elderly are also believed to be the most at-risk community, as they generally experience longer, more severe illnesses which can sometimes be fatal in rare cases, according to the CDC.

Prevention and timely intervention are especially important in such settings, as there is no current treatment for the infection itself but rather its symptoms. One of the most concerning symptoms — dehydration — is the “most common complication that requires medical care” among patients in long-term care facilities, as noted in a study from researchers with Australian National University and the CDC.

Aside from healthcare facilities, the most common setting for a norovirus outbreak is a restaurant or catered event. Outbreaks stemming from food-service facilities such as these, the CDC says, had accounted for around 22% of all reported outbreaks between 2009 and 2013.

Infected workers who spread norovirus particles are “frequently the source” of the outbreaks, according to the agency, and can easily contaminate foods through touch. Most instances involve infected food-service employees handling ready-to-eat foods, though it’s possible for workers to contaminate cooked foods, too.

Outbreaks are also somewhat common in childcare facilities and schools, as well as colleges where students may be more at risk of exposure in dorms or other shared living or studying spaces.

Cruise ships are not common settings for norovirus outbreaks, despite widespread beliefs to the contrary. Cruise Lines International Association (CLIA) — an industry association comprised of major cruise lines — has even sought to dispel the misconception that norovirus is a “cruise ship disease,” citing previous CDC reporting that showed ship-based outbreaks account for less than 1% of total reported outbreaks in the U.S.

The CDC notes, however, that outbreaks on cruise ships can be “especially challenging to control” because of passengers sharing recreational and dining spaces.

No matter where the outbreak occurs, sickened individuals and those caring for them (or living with the ill in close quarters) need to practice good hygiene and take precautions, warns Dr. Scott Harris, the state health officer for the Alabama Department of Public Health, who spoke with NewsNation local affiliate WIAT in response to reports of recent rising cases.

Doctors recommend disinfecting shared surfaces and frequent handwashing — especially after using the bathroom or before preparing food — among other common preventative measures. Otherwise, there’s a significant risk of spreading the illness to vulnerable groups.

“If you’re in a facility like a hospital or nursing home where you have really vulnerable people, you can have some serious effects because of that,” Harris said.