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Common Questions About Influenza

The best way to prevent flu is by getting vaccinated each year. Doctors at University of Utah Health encourage everyone to get a flu vaccine to protect yourself, the people around you, and to potentially avoid serious complications. Here are some frequently asked questions about influenza.

Why is it important to get a flu vaccine?

Transmission of influenza and other respiratory viruses, like COVID-19, increase during the fall and winter months. Vaccination can help protect you from developing serious complications and slows down transmission. During the 2019-2020 flu season, flu vaccination prevented about 7.5 million flu illnesses, according to the Centers for Disease Control and Prevention (CDC).

It's important to get a flu shot every year because just like COVID-19, the flu virus evolves and mutates. Every year, researchers try to predict the predominant strains, which is how the next vaccine for the following year is determined.

Is it influenza or COVID-19?

Doctors determine whether someone has influenza based on a patient's clinical symptoms. Because flu and COVID-19 share similar characteristics, it's important for a patient to have a clinical evaluation and undergo testing.

How long until the flu vaccine takes effect?

It takes about two weeks for your body to develop its defenses.

How effective are flu shots?

Flu shots are not 100% effective, but they help reduce the rates of hospitalization and severity of illness in both adults and children. Data supports the fact that patients who have received a flu shot are less likely to get seriously ill if infected by influenza.

How long will a flu shot protect you?

The flu vaccine generally protects you for five to six months and then steadily decreases after that.

Can the flu shot make you sick?

After getting a flu vaccine, the body ramps up an immune response against antigens from the flu virus. This means the immune system is working to protect you against influenza. The process could cause some mild symptoms such as body aches or a headache.

While your body is building up its immune defenses, it's possible to get sick with the flu or another respiratory virus within that two-week period. During flu season, a lot of respiratory viruses are circulating, so it's very common for children and adults to get other respiratory viruses at the same time.

Who is at high risk for complications from the flu?

Those at high risk of serious complications include children under five, adults 65 and older, pregnant women, and people with chronic medical conditions.

Is it safe to get a flu shot during pregnancy?

Yes, it is safe to get a flu vaccine during pregnancy. After vaccination, pregnant people pass antibodies to their babies that continue to protect the child after it is born. This protection is important because babies cannot get a flu vaccine until they are six months old.

Can face masks help prevent the spread of influenza?

Yes, and they also protect the spread of other respiratory viruses like the common cold. According to the Centers of Disease Control and Prevention (CDC), both COVID-19 and flu can spread between people who are in close contact with one another. These viruses are spread mainly by droplets made when people with the illness (COVID-19 or flu) cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Face masks can help prevent this type of spread from happening.

I am sick with the flu, what should I do?

  • Check with your health care provider about any special care you may need, especially if you are pregnant or have a health condition such as diabetes, heart disease, asthma, or emphysema.
  • Stay home when you are sick until at least 24 hours after the fever is gone without fever-reducing medicines (at least four to five days after symptoms have started).
  • Get plenty of rest.
  • Drink clear fluids (such as water, broth, sports drinks, or electrolyte beverages for infants) to keep from being dehydrated.
  • Cover coughs and sneezes. Clean hands with soap and water or an alcohol-based hand gel often and especially after using tissues and coughing or sneezing into hands.
  • Avoid close contact with others. Do not go to work or school while ill.

When is it safe for children to go back to school after getting the flu?

CDC recommends a child to stay home until they've been without a fever for 24 hours without using fever-reducing medicines.

When should I be seen by a doctor?

If a person is at high risk for complications or has worsening symptoms, they should seek care from their health care provider or an Urgent Care clinic. If a patient has symptoms such as difficulty breathing, bluish lips, signs of dehydration, or are less responsive than normal, they should go to the emergency room.