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Key takeaways
The flu is contagious from one day before symptoms appear to five to seven days after becoming sick, with individuals most contagious in the first three to four days after symptoms begin.
The flu spreads through droplets when an infected person coughs, talks, or sneezes, and can infect others who are up to six feet away or who touch contaminated surfaces and then their face.
Preventative measures against the flu include frequent handwashing, avoiding close contact with sick individuals, covering your mouth and nose when coughing or sneezing, wearing face masks, and staying up to date on vaccinations.
Antiviral medications like Tamiflu can lessen the severity and duration of flu symptoms and may reduce the contagious period if treatment is started within 48 hours of symptom onset.
The flu is a contagious respiratory infection that affects the nose, throat, and lungs. The flu virus, or influenza, spreads via droplets when someone who has it coughs, talks, or sneezes. These droplets can make their way into the noses, mouths, and ultimately the lungs of other people and make them sick. So, how long is the flu contagious for?
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How long can I spread the flu for?
The flu is contagious from the day before symptoms start to five to seven days after becoming sick. The incubation period of the flu, or how long it can take to develop symptoms after exposure and infection, is about one to four days. One reason the flu spreads so quickly is that someone can be contagious and not show signs of being sick until a few days after catching the flu virus.
The contagious periods of the flu, common cold, and stomach bug are very similar. With the common cold, you can become contagious one to two days before symptoms start, and you can remain contagious for up to two weeks. The same is true for the stomach bug, and you won’t stop being contagious for several days after you’ve completely recovered. As far as the coronavirus is concerned, Harvard Health reports that COVID-19 can be contagious 48 to 72 hours before the first onset of symptoms. The contagious period ends about 10 days after symptoms resolve. Some infectious disease experts still recommend 14 days of isolation.
One reason viral infections like the flu are so common is that they can spread easily between people. The Centers for Disease Control and Prevention (CDC) says that the flu can spread from a sick person to healthy people who are only six feet away. This usually happens when the sick person coughs, talks, or sneezes. However, if a healthy person touches a surface contaminated with the flu virus and then that person touches their eyes, nose, or mouth, they’re also at risk for getting the flu.
There are four types of influenza viruses: influenza A, B, C, and D. Type A is the primary cause of flu season epidemics, but influenza B can also cause flu epidemics. Influenza C is known to cause less serious respiratory illnesses. Finally, influenza D viruses aren’t known to infect people and mainly target cattle. Although there are so many influenza strains, they all cause infections that last about the same amount of time. The severity of the illness may vary depending on the strain though.
When am I most contagious?
People with the flu are the most contagious during the first three to four days after symptoms begin.
| How long is the flu contagious? | ||
|---|---|---|
| 1 day before symptoms develop | 3-4 days after symptoms begin | 5-7 days after symptoms begin |
| Start becoming contagious | Most contagious | Still contagious even if you feel completely better |
Note: This table is only a generalization. The CDC reports that young children and people with weakened immune systems may be contagious after seven days.
Symptoms of the flu can start to appear anywhere from one to four days after getting the flu virus, and even though most cases of the flu resolve in a week, symptoms can last up to several weeks for some people. Here are the most common symptoms of the flu:
- Fever
- Cough
- Congestion
- Chills
- Muscle aches
- Body aches
- Headache
- Fatigue
- Sore throat
- Runny nose
How long should I stay home with the flu?
Staying home when you have the flu is important to help you rest and help avoid getting other people sick. The CDC recommends that people with the flu, or people who think they have the flu, should stay home from work at least four to five days after their first symptoms. The CDC also recommends that people with a fever stay home at least 24 hours after their fever goes away without taking any fever-reducing medications. If you’re at work and you start to have flu-like symptoms, it’s best to go home to prevent your coworkers from getting sick.
How can I tell if I’m still contagious?
It can be hard to tell if you’re still contagious even after you’ve recovered from the flu. It’s possible to have the flu for a few days, feel better, and still be contagious days later. In other words, just because you feel better, this doesn’t mean you can’t pass the virus on to someone else. The best way to know if you’re still contagious is to count how many days it has been since the day you got sick. If it’s been seven days or longer since you first started getting symptoms, you probably aren’t contagious anymore.
The flu is contagious regardless of whether or not you have a fever. You’ll still be contagious for five to seven days even if your fever breaks early on. The time it takes to no longer be contagious is just a matter of where you are on the seven-day timeline.
What stops the flu from spreading?
There are multiple ways to avoid getting and spreading the flu. Here are some of the best ways:
- Washing your hands often: This will help protect you from any germs that could make their way into your eyes, nose, or mouth. If you cannot wash your hands with soapy water, then hand sanitizer is the next best thing.
- Avoiding close contact with sick people: Trying your best to stay away from sick people will help keep you from catching the flu. If you’re sick with the flu, limiting your contact with other people will keep you from spreading the flu.
- Covering your mouth and nose when coughing or sneezing: When you’re sick with the flu and cough or sneeze, tiny droplets containing the flu virus can travel through the air and infect other people. Covering your mouth and nose is a great way to help stop this.
- Wearing a face mask: The protection you get from face masks isn’t exclusive to coronavirus. A face mask can protect you from the common cold and flu too.
- Staying up to date on vaccinations: Getting a flu shot is one of the best ways to prevent the flu. Flu vaccines have been proven to reduce the risk of flu illnesses, hospitalizations, and flu-related deaths.
Does Tamiflu shorten the contagious period?
Other than these methods, some antiviral medications may shorten the flu’s contagious period. Tamiflu (oseltamivir phosphate) is a medication used to lessen the severity of symptoms, and shorten the overall duration of illness which in turn may decrease how long someone is contagious. .Studies show that Tamiflu shortens the average length of the flu by one day, but it is important to start treatment as soon as possible from the time of symptom onset – ideally within 48 hours.
Tamiflu can also help prevent the flu if someone’s been exposed to a confirmed case of the flu. However, it’s important to remember that Tamiflu isn’t a replacement for an annual influenza vaccine.
RELATED: Does the flu shot or Tamiflu prevent COVID-19?
How to treat the flu
In addition to Tamiflu, the CDC recommends three other FDA-approved medications to treat (not prevent) the flu, which are Relenza (zanamivir), Rapivab (peramivir), and Xofluza (baloxavir marboxil).
Aside from antivirals, some homeopathic medicines have shown to help treat the flu. “If the flu invades your household this winter, you will be well-prepared by having stocked up on Boiron Oscillococcinum,” says Ken Redcross, MD, author of Bond: The 4 Cornerstones of a Lasting and Caring Relationship with Your Doctor and founder of Redcross Concierge. “Clinical studies show that when used at the first signs, Oscillococcinum helps relieve the duration and severity of flu-like symptoms such as body aches, headache, fever, chills, and fatigue. This homeopathic medicine is widely available in local supermarkets or pharmacies for everyone ages 2 and up.”
If you’re interested in learning more about how to prevent or treat the flu, you can always schedule an appointment with your healthcare provider. With flu season just around the corner, it’s still a good idea to be prepared in case you get sick.
