What exactly is the 24-hour flu and what symptoms does it cause?

Updated: 11:39 PM EST Nov 30, 2022

With the winter months and holiday season on the horizon, you’re likely doing everything in your power to stay healthy. But sometimes getting sick is inevitable and knowing exactly what you’ve come down with becomes the priority to get proper treatment and avoid passing it along to others. The flu and COVID-19 are likely high on your radar, but you should also be aware of 24-hour flu.Believe it or not, even though it's called "the 24-hour flu," it has nothing to do with the flu or flu virus at all. The 24-hour flu is a misnomer because influenza is an upper respiratory tract virus that does not involve the gastrointestinal tract, explained Nicholaos Bellos, MD, an infectious disease expert and the national medical director of extended care services at Quest Diagnostics. People who have the 24-hour flu are actually experiencing a condition known as gastroenteritis, also often referred to as the stomach flu, he says. Gastroenteritis is commonly known as the 24-hour flu because the symptoms it causes may only last a day or two. That's not always true, though, since GI issues caused by this condition can sometimes take up to 14 days to go away, Bellos said.When it comes to the 24-hour flu, you don’t want to mess around. Here’s everything you need to know about this stomach bug, according to doctors. So, what causes the 24-hour flu?“Adult cases are usually caused by norovirus, also known as the winter vomiting bug, rotavirus, or food poisoning,” Bellos said. The virus or contaminated food causes your stomach and intestines to become irritated and inflamed, leading to gastroenteritis and the associated symptoms, he explains.Both the norovirus and rotavirus are spread through coming into contact with someone who has the virus or their unwashed hands (especially after going to the bathroom or changing a diaper) or touching contaminated surfaces. Food poisoning, on the other hand, occurs when someone consumes contaminated food or water, Bellos said.That said, the 24-hour flu is typically not airborne (caused by coughing, sneezing, or laughing), according to Natasha Chhabra, M.D., a gastroenterologist at Gastroenterology Associates of New Jersey. “People can get it through ingestion of contaminated foods, but usually more rapid spread is in crowded areas and more through direct contact rather than respiratory.”What are the symptoms of the 24-hour flu?Symptoms usually appear within four to 48 hours after coming in contact with the virus or eating contaminated foods. They can include abdominal pain, diarrhea, cramps, nausea, vomiting, and sometimes fever, said Dr. Bellos. You may also have body aches, loss of appetite, or extreme fatigue, and dehydration is common if you're throwing up or going to the bathroom a lot. The tricky part is symptoms can be similar to those of the flu or COVID-19. “COVID-19 can cause gastrointestinal symptoms, even when breathing problems are not present, so it’s important to look at other more severe health conditions when experiencing symptoms,” Bellos said. But simple tests can rule out COVID-19, the flu, or bacterial infections.And while anyone can get the 24-hour flu, those with a weakened immune system are at a higher risk, Chhabra said. Young children, elderly people, and anyone who is immunocompromised or taking medications that suppress their immune system are more likely to develop severe symptoms. Does the 24-hour flu really go away in a day?Unfortunately, no. “For most people, the illness goes away in a few days, and you can be contagious from a few days to two weeks or more, depending on which virus caused the gastroenteritis,” Bellos said.However, in the case of the norovirus, you may still be contagious a few days after you recover. The 24-hour flu is very contagious, so the best way to avoid getting others sick is to limit contact, disinfect all surfaces (counters, door handles, faucets, etc.), and practice good hand washing (that means rinsing with soap and water for at least 20 seconds), Bellos said.The virus can also remain in your stool for up to two weeks after recovery, so hand washing after using the bathroom is absolutely essential, he added.How do you treat the 24-hour flu?Most cases go away on their own with rest and plenty of fluids, but Chhabra recommends hydrating with electrolytes, such as drinking Vitamin Water, Gatorade or even Pedialyte. If you’re struggling to keep anything down, drink small amounts of water or electrolyte fluids (two to four ounces) every 30 to 60 minutes, Bellos added. You should also stick to bland foods like bread, crackers, or rice, and avoid anything heavy or flavorful. “Sometimes antidiarrheals like Imodium can be used, but that should be discussed with your doctor before using in case there is an infection that requires more specific treatment like an antibiotic,” Chhabra said.A probiotic supplement may also be helpful to restore the gut flora, which can be thrown off when you’re dealing with an infection or virus. “There's not one probiotic that’s considered much better than others, but a probiotic in general supplies you with good bacteria and can help mitigate symptoms,” Chhabra added.You may not feel the effects of the probiotic right away, but you’ll notice (and feel!) a difference over time. When should you see a doctor?If you have diarrhea that lasts more than several days or notice blood in your stool, then you need to seek medical care, Chhabra said. Prolonged nausea that lasts more than one to two weeks is also a sign that it’s time to check in with your doc. Dehydration is another major concern with the 24-hour flu, so if you feel lightheaded, dizzy, delirious, or have dry mouth, lips, or eyes, then you need to go to the emergency room or urgent care ASAP, Chhabra said.

Many hospital systems across greater Cincinnati are dealing with multiple viruses circulating after Thanksgiving.

"Most of our hospitals have been running fairly close to capacity now anyway for quite some time," professor of infectious disease at UC Health, Dr. Carl Fichtenbaum said.

With COVID-19, the flu, and RSV going around, hospitals like UC Medical Center are feeling the impact.

"What this does with all of the viruses around is it just pushes all of our hospitals in the area to just be a little bit fuller. The emergency rooms are just a little bit more crowded," Fichtenbaum said.

According to the Health Collaborative, COVID-19 hospitalizations across Ohio counties in greater Cincinnati are at 176 patients. That's 41 more than Friday. About 180 people are hospitalized with the flu. It's a major spike from last week.

"It was a pretty significant increase of flu hospitalizations over the past few days. It's really spun up the hospital operations of it," vice president of clinical strategies for the Health Collaborative, Tiffany Mattingly said.

Mattingly says health systems are trying to keep up.

"The majority of them have you been at capacity at some point over the past week or so," Mattingly said.

While we work through these viruses, experts predict there may be more on the way.

"I suspect we'll see some more stuff because this is really the first full year that everybody's back in circulation not wearing masks and we're just sharing viruses," Fichtenbaum said.

Fichtenbaum says this is one of the most potent flu seasons since 2009. That's why he's urging people to roll up their sleeves and get the flu vaccine sooner rather than later.

La Dallas Mitchell is working overtime to care for her daughter.

"It's just been nonstop," Mitchell said. "She's probably been sick like five times."

At the same time, parenting means working around that sickness.

The U.S. is the only developed country that does not guarantee any paid sick leave, according to the Center for Economic Policy and Research, though some states like New York, New Jersey and California have laws with requirements.

Medical experts say the surge of viruses right now highlights the need for paid sick time off.

"With RSV, COVID and the flu, this is very taxing to the health care system but also taxing to our families," said Dr. Willie Underwood, with the American Medical Association. "People get sick and ill; they can't work. They have increased health care costs. It's detrimental to us."

In October, a record high 104,000 Americans missed work due to "childcare problems," according to the Bureau of Labor Statistics.

A recent Robert Wood Johnson Foundation report found workers lost $28 billion in wages during 2020 to 2022. Women, Latino, and Black workers felt the brunt of it. It also found people making less than $25,000 a year were about 2.5 times more likely to not have paid sick leave compared to someone making $100,000.

Epidemiologist and research director Mona Shah worked on the foundation report.

"For a family member who had to take off a week of work to take care of themselves or their child, that meant they lost an average of $815 in wages," Shah said. "That would have huge implications for paying for food, housing, health care, gas and other essentials."

SEE MORE: Doctors: Get Your Flu, COVID Vaccines Now To Be Safe During Holidays

Shah says when someone works while they or a loved one is sick, it impacts more than that single household.

"They're working when they're sick, and they're potentially impacting the people that they come across, whether at work or at school, and so it's really a compounding effect," Shah said.

She said that's why paid time off is important for a community to stay healthy, especially during busy holiday seasons.

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In Iowa, the Southeast Warren school district dismissed classes at 1:30 p.m. on Monday and canceled classes for Tuesday because so many kids are out sick.

Families received an email alerting them of the changes.

"Right now, we're seeing a lot of strep throat and some RSV in children and unfortunately the supply for these antibiotics and over-the-counter products are in very short supply," said John Forbes, the owner of Medicap Pharmacy.

Forbes says the shortage is putting them in a tough position.

Typically, his pharmacy fills multiple Amoxicillin prescriptions every day.

"Right now we have just one bottle left in the pharmacy," Forbes said.

Forbes says this is the first time he's seen a shortage this severe.

His wholesalers tell him it'll be more than a week before they will be getting these critical medications.

And keeping that in mind, Forbes says it's important to get your vaccinations to help stop the spread of illness.

"By you getting the vaccines, you also protect yourself but you also protect people around you. So you can reduce the risk of spreading this virus to other people," Forbes said.

Imagine if when you got sick, you knew exactly what you were sick with, and therefore had an idea of how it spreads and how to treat it. That could be a reality in the future with the prevalence of at-home testing for other viruses beyond COVID.

Dr. Lisa Maragakis is a professor of medicine and infectious diseases at Johns Hopkins University School of Medicine. She says the convenient and easy-to-use at-home tests for COVID-19 were a game changer during the pandemic.

"And this really raises the question of why we don't have more widespread at-home testing for other respiratory viruses like influenza or respiratory syncytial virus RSV," Dr. Maragakis said.

The so-called 'tripeldemic' of COVID-19, influenza and RSV last year brought to light the need for at-home testing for other viruses.

"One new challenge in respiratory virus season is having co-circulation of influenza, RSV and SARS-CoV-2, the virus that causes COVID-19," Dr. Maragakis said. "And since we do have treatments that are different for the different viruses, we do need to know and cannot make the kind of empiric decisions or diagnoses that we used to be able to make in past flu seasons."

Dr. Maragakis says the science is there to create these types of tests, but they aren't widely available yet. Global life sciences company Labcorp announced last year emergency-use authorization from the FDA for an at-home collection kit that simultaneously detects COVID-19, influenza, or RSV.

You can order one online that will be shipped to your house free of charge if you have insurance. Without insurance, it's $169 dollars.

However, it's not a rapid test. It's a PCR test that you send to a lab, so it takes several days to get results. As at-home testing becomes more prevalent, Dr. Maragakis says public health leaders will need to take new challenges into consideration.

"We know, right now, that the publicly reported numbers for COVID-19 are just the tip of the iceberg because so many people are being diagnosed by these at-home tests and those data don't flow into the reported numbers," Dr. Maragakis said.

Dr. Maragakis says one solution could be developing a way for people to self report data from at-home tests. The other limitation is that not everyone may use the test correctly, and results could be inaccurate. Until health companies can provide convenient at-home tests for other viruses, Dr. Maragakis says your health care provider still offers the most precise test results.

The US Centers for Disease Control and Prevention issued a health advisory on Thursday warning doctors and other healthcare providers about the rise in respiratory syncytial virus (RSV) across the south.

According to the CDC, RSV is primarily spread via respiratory droplets when a person coughs or sneezes through direct contact with a contaminated surface.

It can cause bronchiolitis and pneumonia, especially in children under the age of one.

The CDC added that older adults with chronic medical conditions are also at risk.

"Due to this increased activity, CDC encourages broader testing for RSV among patients presenting with acute respiratory illness who test negative for SARS-CoV-2, the virus that causes COVID-19," the CDC wrote in the advisory. "RSV can be associated with severe disease in young children and older adults. This health advisory also serves as a reminder to healthcare personnel, childcare providers, and staff of long-term care facilities to avoid reporting to work while acutely ill – even if they test negative for SARS-CoV-2."

Although RSV infections occur primarily during the fall and winter cold and flu season, in March, the CDC saw an increase of RSV being reported by the National Respiratory and Enteric Virus Surveillance System, which is a nationwide laboratory-based surveillance network.

The CDC said each year, between 100-500 children under 5 years old and 14,000 adults older than 65 die from the virus.

The agency recommended that clinicians test patients who show signs of acute respiratory illness who test negative for the coronavirus.