How to protect yourself against the ‘winter vomiting disease’

It’s the holiday guest no one invited.

The notorious “winter vomiting disease” is spreading rapidly across the country, with cases of the potentially deadly virus doubling over the past few months as Americans head into peak party season.

Health officials are sounding the alarm, urging the public to take steps to protect themselves from the highly contagious stomach bug. Here’s everything you need to know to stay one step ahead of it.

What is the “winter vomiting disease”?

Better known as norovirus, this microscopic menace is the nation’s leading cause of vomiting and diarrhea from acute gastroenteritis, which inflames the stomach and intestines, according to the CDC.

It’s also the top source of foodborne illness in the US, responsible for nearly 60% of all cases.

Each year, about 2,500 norovirus outbreaks are reported nationwide, resulting in roughly 900 deaths. The infection also drives 109,000 hospitalizations, 465,000 emergency department visits and up to 21 million illnesses annually.

What are the symptoms of norovirus?

The most common are nausea, vomiting, diarrhea and stomach pain, with some people also developing a headache, fever or body aches, according to the Cleveland Clinic.

Symptoms typically hit 12 to 48 hours after exposure and usually clear on their own within 24 to 72 hours. There’s no cure or specific treatment for norovirus, but staying hydrated is essential to replace lost fluids.

While most people recover quickly, adults 65 and older, young children and those with weakened immune systems face a higher risk of severe illness or death.

How does norovirus spread?

Primarily through contact with the virus, which is present in the vomit or feces of an infected person. You can continue spreading the virus for up to two weeks after you start feeling better.

People can become infected by having direct contact with someone who is sick, consuming contaminated food or water, or touching contaminated surfaces and then touching their mouth.

“We hear about it on cruise ships because you’ve got these packed environments, but cruise ships only account for about 1% of outbreaks,” Dr. Joanna Turner Bisgrove, a family physician and assistant professor of family medicine at Rush University Medical Center, told the American Medical Association.

Norovirus most often spreads in health care facilities, restaurants, catered events, schools and child care centers, Bisgrove said.

What are norovirus cases like now?

Norovirus levels in wastewater have jumped 69% nationwide since October, with the Northeast and Midwest seeing the biggest increases, according to data from WastewaterSCAN, a Stanford University-led tracking tool.

“Right now, we’re in the high category for norovirus at the national level,” Amanda Bidwell, scientific program manager for WastewaterSCAN, told NBC News.

The latest CDC data shows that 14% of norovirus tests are now coming back positive, up from roughly 7% three months ago.

That’s still below last winter’s record-breaking surge, when positive tests peaked at nearly 25%.

How to stop the spread of norovirus

First: wash your hands often with soap and water for at least 20 seconds, the CDC recommends.

That’s especially important after using the restroom, changing diapers, before eating or handling food, and before giving medicine to yourself or someone else.

Notable, unlike for many other viruses, hand sanitizer is not a substitute for hand washing.

You should also disinfect frequently touched surfaces, like counters, doorknobs and cell phones, as well as children’s toys.

But, as Bisgrove notes, “getting norovirus off of surfaces is tricky because it is resistant to most disinfectants and hand sanitizers.”

“In fact, norovirus can stay on food, countertops and serving utensils for up to two weeks, even at freezing temperatures and until heated to above 140º F,” she said.

The EPA lists disinfectants that are effective against norovirus. A solution of 5 to 25 tablespoons of household bleach (5.25%) per gallon of water typically works.

To reduce the risk from contaminated food, the CDC advises cooking items to the recommended internal temperature — at least 145º F for most foods, especially shellfish. Fruits and vegetables should also be washed thoroughly before eating.

If you’re sick, stay home and avoid gatherings for at least two days after your symptoms stop, since you’ll still be contagious.

Avoid close contact with others and don’t handle food. Make sure to clean bathrooms thoroughly and wash laundry in hot water.

Wearing gloves while cleaning — and throwing them away afterward — adds an extra layer of protection.