By Alice || Edited by Go Ask Alice Editorial Team || Last edited Sep 12, 2024

Cite this Response

Alice! Health Promotion. "Flu Facts." Go Ask Alice!, Columbia University, 12 Sep. 2024, https://goaskalice.columbia.edu/fact-sheets/flu-facts. Accessed 21, Nov. 2024.

Alice! Health Promotion. (2024, September 12). Flu Facts. Go Ask Alice!, https://goaskalice.columbia.edu/fact-sheets/flu-facts.

What is the flu?

Influenza, also known as the flu, is a virus that has many strains and appears in the respiratory system. It can infect and cause symptoms in the throat, nose, and, in some cases, the lungs. These symptoms can range from mild to severe, and in some rare cases, cause death. Most people recover from the illness in a few days; however, some symptoms may last up to two weeks. How strong your symptoms are is dependent on which flu strain you’re infected with, your vaccination status, pre-existing health conditions, and your age.  

How is the flu spread?

The flu virus spreads through the droplets created when an infected person sneezes, coughs, or speaks. You may be in close enough contact for these droplets to reach your nose or mouth, causing the virus to spread. It’s also possible that you could contract the flu if you touch your nose, mouth, or eyes after touching an object or surface that has the flu virus on it.  

If you get infected, you can still spread the flu, even if you aren’t showing symptoms yet. The first three days of infection are when you're most contagious, but you may still be contagious for up to a week after you’ve been infected. People with weakened immune systems, like children, may be contagious for more than a week.  

What are the symptoms of the flu?

Symptoms of the flu typically show up within one to four days after infection. These symptoms may include: 

  • Fever or chills 
  • Cough or sore throat 
  • Stuffy or runny nose 
  • Body or muscle soreness 
  • Eye pain 
  • Headaches 
  • Tiredness or weakness 
  • Vomiting or diarrhea 

List adapted from Centers for Disease Control and Prevention and Mayo Clinic

Some severe impacts of the flu could result in other concerns such as: 

  • Ear or sinus infections 
  • Bacterial pneumonia 
  • Bronchitis 
  • Acute respiratory distress syndrome 
  • Muscle, heart, or brain inflammation 
  • Worsening of prior chronic medical conditions 

List adapted from Centers for Disease Control and Prevention and Mayo Clinic

What should you do if you get the flu?

It’s recommended that you limit your contact with other people when you have the flu. If you are around other people, consider wearing a mask. If you don’t have a mask and need to cough or sneeze, consider doing so with a tissue or into the inside of your arm. Taking these steps can help reduce the likelihood of passing the virus on to someone else.  

How can you treat the flu?

There’s no cure for the flu. Treatment usually involves managing your symptoms, typically by using some at-home remedies in order to feel better. Some of these include: 

  • Getting plenty of rest. 
  • Drinking lots of liquids. 
  • Taking acetaminophen or ibuprofen to reduce fever and muscle aches. 

List adapted from Mayo Clinic

When should you seek medical care?

People at higher risk of developing complications may choose to seek medical care once they notice flu symptoms. Some factors that may heighten the risk of complications include: 

  • Being 65 years or older 
  • Being younger than five years 
  • Chronic Illness 
  • Body mass index of 40 or higher 
  • Pregnancy 
  • Long-term use of aspirin under the age of 20 

List adapted from Centers for Disease Control and Prevention and Mayo Clinic

Whether you’re at risk of complications or not, it’s important to be aware of other emergency symptoms. Seeking medical care is recommended if you experience any of the following symptoms: 

  • Chest pain 
  • Difficulty breathing 
  • Seizures 
  • Prolonged dizziness 
  • Severe weakness or muscle aches 
  • Worsening of prior medical conditions 

List adapted from Mayo Clinic

If you have a symptom that causes distress or discomfort, whether or not you’re at higher risk of complications or experiencing emergency symptoms, it may still be beneficial to seek medical care.

How can you reduce your risk of getting the flu?

Flu season typically occurs in October but can vary depending on where you’re located. During this time, it’s recommended to take precautions to lower your risk of infection. Keeping your distance from those who display symptoms of sickness, avoiding crowed areas, washing your hands throughout the day, and wearing a mask are some ways you may choose to protect yourself. While these actions may give you some additional protection against the flu virus, getting the flu vaccine is often the most effective strategy to protect you against contracting the virus.

What should you know about the vaccine?

The flu vaccine protects against the influenza viruses that are predicted to be most common when flu season begins. The flu vaccine does not protect against other illnesses. It’s often given with a needle, but there’s also a nasal spray option for those who are eligible. In addition to the different ways the vaccine is given, there are also different manufacturers and variations of the flu vaccine available. Once you receive the vaccine, it can take up to two weeks for your body to form protection against the viruses.

While vaccines contain strains of the flu viruses, they aren’t infectious, have been killed, or only contain proteins from the virus. Therefore, you cannot get the flu from the flu vaccine.  

How effective is the flu vaccine?

Research shows that getting the flu vaccine is highly effective at protecting you from flu infection. That said, the degree of effectiveness can change depending on your pre-existing health conditions and the flu strains that end up being most common in a given year.  

It should be noted that receiving the vaccine doesn’t make you immune to every type of flu virus. You may still become infected, even after being vaccinated, but it’s been found that the severity of your symptoms is likely to be reduced.  

What are the side effects of the vaccine?

Side effects of the vaccine can be similar to, but are often milder than, symptoms of the virus itself.  

It’s rare, but possible, to have an allergic reaction to the vaccine. Some symptoms of an allergic reaction include: 

  • Difficulty breathing 
  • Wheezing or hoarseness 
  • Hives 
  • Weakness 
  • Paleness 
  • Fast heartbeat 
  • Dizziness 

List adapted from Centers for Disease Control and Prevention

If you do find yourself experiencing an allergic reaction, it’s important that you seek immediate medical care.

Is the vaccine right for you?

The vaccine is recommended for most people six months and older. Because the vaccine changes year to year to account for new virus strains, it’s recommended that you get vaccinated each year. This is especially true for those who are at high risk of developing complications from the flu.  

That being said, those with severe allergies, are advised to take caution when considering getting vaccinated. If you’re allergic to any of the ingredients in the flu vaccine or have previously had an allergic reaction to it, it’s recommended that you consult with a health care professional before receiving the vaccine.

Where can you get the vaccine?

Vaccines can be found at most pharmacies or drug stores across the United States. Doing an internet about where you can the vaccine may also produce results specific to your location. Additionally, you can use Vaccines.gov’s VaccineFinder to help you identify a location using your five-digit zip code.