Summer Flu, Contagious For How Long?

Summer Flu, Contagious For How Long?

Summer is here, and for many, that means fun in the sun, beach trips, and outdoor activities. But the summer months also bring a rise in seasonal influenza or “summer flu.” Just when you thought flu season was behind us, another one pops up. So how long is the summer flu contagious? Read on to learn more.

What Is Summer Flu?

The flu is caused by influenza viruses that infect the respiratory tract. There are four types of influenza viruses – A, B, C, and D. Influenza A and B cause seasonal epidemics nearly every winter in the United States. The flu viruses are spread mainly by tiny droplets made when people with the flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people nearby.

Summer flu or seasonal influenza refers to flu activity that peaks in the summer months. The viruses that cause summer flu are similar to the ones that lead to winter flu seasons. The only difference is the timing.

Just like winter flu, summer flu causes fever, cough, sore throat, runny or stuffy nose, muscle aches, headaches, fatigue, and sometimes vomiting and diarrhea. Summer flu can range from mild to severe. While most people recover in a week or two, some develop complications like pneumonia which can be life-threatening. People at highest risk include young children, adults over 65, pregnant women, and those with underlying health conditions.

How Long Is Summer Flu Contagious?

People with summer flu are most contagious in the first 3-4 days after the illness starts. However, some people, especially children and people with weakened immune systems, might be able to infect others for a week or longer after getting sick.

In general, the contagious period for summer flu is:

  • 1 day before symptoms develop
  • 3-4 days after symptoms start
  • 5-7 days after symptoms start for young children and immunocompromised individuals

So it’s best to avoid contact with anyone showing flu symptoms for at least 7 days. However keep in mind, that some people infected with the flu virus have no symptoms yet can still spread it to others.

How Does Summer Flu Spread?

As mentioned earlier, influenza viruses spread through respiratory droplets released when infected people cough, sneeze, or talk. These droplets can land directly in the mouths or noses of those nearby. Less often, a person might get the flu by touching a surface or object contaminated with the virus and then touching their own eyes, nose, or mouth.

That’s why hand washing is key to avoiding spreading the summer flu. Make sure to wash your hands thoroughly with soap and water for at least 20 seconds. If soap and water aren’t available, use an alcohol-based hand sanitizer.

To further reduce the spread, make sure to cough or sneeze into a tissue or your elbow rather than your hands. Put used tissues immediately in the trash. Clean and disinfect frequently touched surfaces like doorknobs, phones, remotes, keyboards, and tablets.

Avoid close contact with anyone showing flu symptoms. And if you’re sick, stay home to keep from infecting others.

How Long Does Summer Flu Last?

The duration of summer flu illness can vary but for otherwise healthy adults it typically lasts about a week. Here’s a general timeline:

  • Days 1-3: Symptoms start abruptly, often with a fever, cough, sore throat, runny nose, headaches and body aches. Fatigue sets in.
  • Day 4: Fever and muscle aches may lessen but fatigue and cough often persist. Some people, especially children, may develop vomiting and/or diarrhea.
  • Days 5-7: Cough and fatigue improve but may linger for a week or more. Complete recovery can take 1-2 weeks.

However, the duration can be longer in high-risk groups like young children, older adults, and those with chronic medical conditions. See a doctor right away if symptoms don’t improve after a week, or earlier if they suddenly get worse.

Who’s Most At Risk For Summer Flu?

Anyone can get summer flu but certain groups are more susceptible to flu-related complications if they get sick. High-risk groups include:

  • Children under 5: Their immune systems aren’t yet fully developed.
  • Adults 65 and older: Immune defenses weaken with age.
  • Pregnant women: Pregnancy weakens the immune system and makes it harder to fight infection.
  • Those with chronic conditions: Such as asthma, heart disease, diabetes, cancer, or HIV/AIDS.
  • Immunocompromised: Such as those on chemotherapy or immune-suppressing medications like steroids.

High-risk individuals must get an annual flu vaccine. While the vaccine isn’t 100% effective, it greatly reduces the risk of severe illness and complications.

How To Treat Summer Flu

Most cases of summer flu can be managed at home with rest, fluids, and over-the-counter medications:

  • Rest: Avoid strenuous activity while sick. Get extra sleep to allow your body to heal.
  • Drink fluids: Stay hydrated with water, broth, sports drinks, or electrolyte beverages.
  • Take fever reducers: Use ibuprofen (Advil) or acetaminophen (Tylenol) as needed for fever and body aches.
  • Try cough/cold medications: Use as directed for cough, congestion, and sore throat.
  • Avoid decongestant sprays: Prolonged use can worsen symptoms.

See a doctor if symptoms don’t improve after a few days or get suddenly worse. Those at high risk should contact a doctor right away when flu symptoms start for evaluation and possible antiviral medication.

How To Avoid Summer Flu

The best defense is to get a flu shot each fall. Good health and hygiene habits also help prevent infection:

  • Get adequate sleep and eat a balanced diet to keep your immune system strong.
  • Wash hands frequently and sanitize commonly touched surfaces.
  • Avoid touching your eyes, nose, and mouth.
  • Cough/sneeze into a tissue or elbow rather than hands.
  • Avoid close contact with anyone showing flu symptoms.
  • Stay home when sick to keep from spreading the illness.

Flu viruses are always changing so new flu vaccines are made each year. Be sure to get an annual flu shot to boost protection.


While we usually associate flu with the winter months, summer flu is a reality. The viruses that cause summer flu are contagious for about one week. Children and those with weakened immune systems can potentially spread the virus for even longer after getting sick.

To avoid getting and spreading summer flu, get an annual flu shot, practice good hygiene, and stay away from anyone exhibiting flu symptoms for at least seven days. See a doctor right away if your symptoms don’t improve or get worse. With some sensible precautions, you can stay healthy and enjoy the summer months.


How long is someone contagious before showing summer flu symptoms?

People can spread summer flu starting about one day before flu symptoms appear. Peak contagiousness is during the first 3-4 days after illness onset.

Can you get summer flu more than once?

Yes, it’s possible to get sick with summer flu more than once because flu viruses constantly change. Exposure to a new strain you haven’t encountered before can lead to reinfection. An annual flu shot offers optimal protection.

Does summer flu go away on its own?

In otherwise healthy individuals, summer flu will typically go away within 7-10 days without medical treatment. Rest, fluids, and over-the-counter symptom relievers help you recover. Those at high risk should see a doctor as they may need antiviral medication.

Is summer flu worse than winter flu?

Most symptoms of summer and winter flu are similar. Neither one is necessarily worse than the other. However, winter flu tends to lead to more hospitalizations and deaths mainly due to the sheer number of people infected during winter flu season.

What’s the most common summer flu symptom?

The most common symptoms of summer flu are fever, cough, sore throat, runny nose, body aches, headaches, chills, and fatigue. Some people, especially children, may also have vomiting and diarrhea.

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