The stomach flu, also known as viral gastroenteritis, is a common illness caused by viruses that infect the digestive system. It’s characterized by symptoms like diarrhea, vomiting, nausea, and abdominal cramps. Since it’s very contagious, it’s natural to worry that if one person in the family gets sick, will everyone get infected? Let’s take a closer look at how stomach flu spreads and how you can protect your family.
How does the stomach flu spread?
There are a few ways stomach flu spreads from person to person:
- Having direct contact with an infected person’s vomit or stool
- Consuming contaminated food or water
- Touching contaminated surfaces or objects and then touching your mouth
- Inhaling particles from an infected person’s sneeze or cough
The viruses that cause stomach flu spread through what’s known as the fecal-oral route. This means the virus is shed in the stool and vomit of an infected person. If someone else swallows particles of the virus, they can become infected. This is why hygiene plays such an important role in preventing transmission.
Stomach flu is very contagious because only a small number of viral particles can make someone ill. Plus, people infected with stomach flu are the most contagious during the first few days of illness, when diarrhea and vomiting are worst. But some people can spread the illness for weeks after symptoms end.
What is the incubation period?
The incubation period is the time between being exposed to a virus and when symptoms start. For stomach flu, the incubation period ranges from 1-4 days. Most people develop symptoms within 1-2 days after exposure.
This short incubation period makes stomach flu spread rapidly. By the time someone realizes they’re sick, they may have already been spreading the illness for a day or two. Knowing the typical incubation period can help you figure out where and when you may have been exposed.
How long does the stomach flu last?
Symptoms of stomach flu typically last 1-3 days, but can linger for up to a week in some people. Adults tend to recover more quickly than children. Here is the usual course of the illness:
- Day 1 – Symptoms start suddenly, with nausea, vomiting, diarrhea, abdominal pain
- Day 2 – Symptoms peak in severity
- Day 3 – Vomiting subsides, but diarrhea may persist
- Days 4-7 – Diarrhea and abdominal discomfort improve
Keep in mind every case is different. Some people only have symptoms for 24 hours, while others feel sick for up to 10 days. Staying hydrated by drinking clear fluids is key during illness. See a doctor if symptoms don’t improve after a few days or if you see signs of dehydration.
How long is a person contagious with the stomach flu?
People with stomach flu are most contagious during the first 3 days of illness. The viruses can be shed in stool for 2 weeks or longer after symptoms end. Some people may be contagious for up to 4 weeks, even if they feel better.
This long period of contagiousness makes the viruses that cause stomach flu so easily transmittable. Even if you feel back to normal, you could still infect others. Carefully wash hands with soap and water after using the bathroom until at least 2 weeks after illness. Disinfect any soiled laundry and surfaces.
What are the chances my whole family will get sick?
It depends on a few factors:
- How contagious the virus is – Norovirus is the leading cause of stomach flu and is highly contagious
- How closely together your family lives – More contact raises risk
- Your family’s hand hygiene and cleaning practices
- Who got sick first – The index case is the most contagious
- Your family’s immunity – Previous exposure provides some protection
Household outbreaks are common because families live so closely together. It’s very hard to isolate a sick family member. Everyone shares bathrooms, eats meals together, and touches common surfaces. While it’s difficult to prevent, good hygiene can reduce transmission.
Focus extra cleaning efforts on the bathroom and kitchen. Use a disinfectant on surfaces like toilet handles, doorknobs, and the refrigerator handle. Make sure everyone washes hands frequently, especially before eating. Have your sick family member wear a mask and disposable gloves if they must be around others.
Following these precautions gives your family the best chance of staying healthy. But because stomach flu is so contagious, there’s still a high risk of multiple household members getting sick.
Who is most at risk in my family?
Certain groups are more likely to develop severe illness or complications from stomach flu. This includes:
- Young children under age 5
- Adults over age 65
- Pregnant women
- People with weakened immune systems
- People with chronic diseases like diabetes or kidney failure
Dehydration is the most common complication, especially in vulnerable groups. Watch for signs of dehydration like excessive thirst, infrequent urination, and dark urine. If you see these, call your doctor right away.
To prevent dehydration, the CDC recommends drinking these fluids if tolerated:
- Water
- Fruit juice without pulp
- Weak tea
- Clear broths and soups
- Caffeine-free soft drinks
- Gelatin
- Sports drinks like Gatorade
- Oral rehydration solutions like Pedialyte
Avoid milk, caffeinated drinks, and apple juice until the diarrhea starts improving. Getting fluids down is most important, even if everything comes back up. Frozen popsicles are an easy way to hydrate kids.
In severe cases, hospitalization for IV fluids may be required. Talk to your doctor if symptoms are not resolving, especially in vulnerable groups.
How can I prevent stomach flu from spreading through my family?
Here are some key tips to prevent household spread:
- Isolate sick family members as much as possible
- Everyone should frequently wash hands with soap and water
- Immediately clean up any vomit or diarrhea
- Use a disinfectant approved to kill viruses
- Avoid sharing food, drinks, and utensils
- Stay home until at least 48 hours after symptoms end
- Wear disposable gloves for diaper changes or helping sick family
- Wipe down frequently touched surfaces like phones, remotes, counters
- Machine wash contaminated laundry on hot, using bleach if recommended
Emphasize that everyone needs to wash hands frequently, especially before eating or touching their face. Have hand sanitizer readily available. Postpone any family gatherings or travel plans if someone is sick. Stay on top of disinfecting and limit sick family members to one area of the home if possible.
Following prevention guidelines diligently gives your family the best chance of staying well. But you can’t eliminate risk completely when living in close quarters with a stomach flu case. Get ahead of dehydration, and call your doctor with any concerns.
Should I take my family to the doctor?
In most cases, you don’t need to visit the doctor for stomach flu. There aren’t any medications that specifically treat the viruses, so the focus is on managing symptoms.
See your doctor if:
- Symptoms last more than 3 days in adults, or more than a few days in kids
- You see signs of dehydration
- You have a high fever above 102 F
- You recently traveled internationally
- You have bloody diarrhea or severe abdominal pain
- You have a weakened immune system from chronic illness or medications
For infants under 6 months old, call the doctor any time they have diarrhea or vomiting. Dehydration develops quickly at this age. Urine output and tears are the best ways to assess hydration.
Your doctor may order tests on a stool sample to confirm the cause. Getting an accurate diagnosis can help if symptoms don’t resolve. In serious cases, hospitalization for fluids may be required.
Should I give my sick family members medication?
There are no medications that cure viral gastroenteritis. Antibiotics only work against bacteria and are not effective for stomach flu. However, some medications can help manage nausea, vomiting, diarrhea, and dehydration:
- Over-the-counter anti-nausea/vomiting meds like Emetrol, Bonine, Dramamine (use carefully in kids)
- Over-the-counter anti-diarrheal meds with loperamide like Imodium (not for kids under 2 years)
- Oral rehydration solutions to prevent and treat dehydration
- Prescription anti-nausea meds like Zofran or Phenergan (for severe nausea/vomiting)
Carefully review dosing guidelines and side effects before giving any new medication to a sick family member. For small children, talk to your pediatrician about using these types of medicines. Focus on fluids and rest to help everyone recover.
When can my family return to work and school after stomach flu?
The CDC provides these recommendations for when people with stomach flu can return to public settings:
- Adults should stay home until at least 48 hours after the last episode of diarrhea or vomiting
- Kids should stay home until they are diarrhea/vomit-free for 24 hours
- Anyone who handles or prepares food should stay home for 48-72 hours after symptoms end
- Some businesses or schools may have more stringent policies, so follow guidelines
Even once symptoms resolve, people can potentially still shed virus for several weeks. When returning to school and work, be extra diligent about handwashing to avoid infecting others. Disinfect items you take into public like phones, bags, and laptops.
Listen to your body and don’t return too soon. Coming back before you’ve fully recovered often leads to relapse or spreading illness. Discuss telework options with your employer if you need more recovery time.
How long does stomach flu immunity last?
After recovering from stomach flu, your body builds up antibodies that provide some future protection. But immunity varies based on:
- Your age and health status – Weaker immunity means less protection
- The specific virus – Some viruses provide longer lasting immunity than others
- Re-exposure – Repeated exposures can boost immunity
Adults tend to acquire immunity more quickly and retain it longer than children. But even adults’ immunity declines over time. And because there are multiple viruses that cause stomach flu, you’re never fully immune. Getting sick with norovirus may only provide immunity against that strain, not others.
On average, adults seem to have around 6-14 months of protective immunity after infection. Children may only be protected for 2-6 months. So while some temporary protection develops, it’s still very possible to get stomach flu multiple times per year.
Should I disinfect my whole house if my family gets sick?
It’s smart to do a thorough cleaning when you have a stomach flu outbreak in your home. The goal is to eliminate any lingering traces of virus on household surfaces. Here are some tips:
- Wear disposable gloves and mask while cleaning
- Open windows if weather permits while disinfecting
- Focus on high-touch surfaces – doorknobs, counters, sinks, toilets
- Use a disinfectant designed to kill viruses and allow proper contact time
- Machine wash all towels, sheets, and clothing with hot water
- Empty vacuum canister contents carefully after use
- Clean floors last, starting from the back of the house forward
Regular household cleaners and soap won’t necessarily destroy stomach flu viruses. Look for products registered with the EPA as being effective against norovirus. Bleach solutions may also be used.
It can be daunting to thoroughly disinfect a whole house. Start with high priority germ hot spots like the bathroom and kitchen. Focus on areas the sick person touched. You don’t necessarily need to sanitize every inch if thorough daily cleaning practices are followed.
Should my family avoid public places after exposure?
If someone in your household currently has stomach flu, it’s wise for the whole family to avoid public places as much as possible. This helps limit the spread of infection. Skip leisure activities like eating out, movies, sports games, and parties.
Exposure is hardest to avoid at school or work. Many employers won’t allow extra sick time unless you’re actively ill. Do your best to limit contact with others and frequently disinfect work or school items you touch.
Once the household outbreak resolves, continue practicing good hygiene when out. Wash hands before eating and avoid people showing illness. Those who are still symptomatic should stay home. Getting back to routines is fine if heightened cleaning and hand hygiene continue, especially after using bathrooms.
When to seek emergency care
In most cases, stomach flu runs its course at home with supportive care. But certain severe symptoms require prompt medical treatment. Seek emergency care if you experience:
- Persistent vomiting that prevents keeping fluids down
- Blood or pus in stool
- Black, tarry stools
- Severe dehydration
- Frequent fainting or dizziness upon standing
- High fever above 104 F
- Confusion or disorientation
- Severe abdominal or rectal pain
Signs of dehydration requiring emergency treatment include:
- Urinating less often than every 8 hours
- Racing heart rate
- Fainting or faintness
- Muscle cramps
- Dry mouth and tongue
- No tears being produced
- Sunken eyes
- Weakness or lethargy
- Skin tenting – loose skin stays pinched upward
Don’t wait with severe dehydration – it can lead to kidney failure, seizures, and low blood volume shock. Seniors with stomach flu are especially prone to complications. Seek care immediately if you see multiple signs of dehydration or any other concerning symptoms.
Key Takeaways
- Stomach flu is very contagious and household outbreaks are common
- Good hygiene like handwashing can lessen, but not eliminate, household spread
- Isolate sick family members and disinfect high-touch surfaces
- Treatment focuses on hydration and managing symptoms
- Call your doctor if you have concerns or if anyone develops signs of dehydration
- Most cases improve within 3-7 days
While certainly unpleasant, most cases of stomach flu resolve on their own within a week. Drink plenty of fluids, get lots of rest, and call your doctor with any concerns. With diligent hygiene and cleaning practices, you can limit the virus spreading through your whole family.