Flu Q&A

How serious is the flu?
The flu, or seasonal influenza virus, is extremely unpredictable. Its severity can vary widely from one season to the next depending on many things, including the strains of flu spreading, availability of vaccines, how many people get vaccinated and how well the flu vaccine is matched to the flu viruses circulating each season.

The bottom line: Take the flu seriously, take precautions, stay home if you are sick and call your doctor if symptoms are severe or prolonged — or if you develop complications.

Why is it especially important to get the flu vaccine this season?
According to the Centers for Disease Control and Prevention (CDC), getting a flu vaccine will be more important than ever this flu season, especially because it is likely that that flu viruses and the virus that causes COVID-19 will both be spreading this fall and winter. The CDC recommends that individuals over 6 months of age get vaccinated in September and October.

Who is at greatest risk?
Certain people are at greater risk for serious complications if they get the flu. They include:

  • People over age 65
  • Young children under the age of 5 and especially those under the age of 2
  • Pregnant women
  • People with certain health conditions (such as asthma, diabetes or heart disease)
  • People who live in facilities like nursing homes

If I get the flu vaccine, do I still need to wear a mask?
Yes. Regardless of whether you have the flu vaccine or not, you should continue to wear a face mask or face covering to prevent the spread of COVID-19.

What are the symptoms of the flu?

  • Fever* or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may diarrhea and vomiting, though this is more common in children than in adults.

*It’s important to note that not everyone with the flu has a fever.

How long is the incubation period of the flu? 
People with flu are most contagious in the first three to four days after their illness begins. Most adults may be able to infect others beginning one day before symptoms develop and up to five to seven days after becoming sick. Children and some people with weakened immune systems may pass the virus for longer than seven days.

Symptoms can begin about two days (but can range from one to four days) after the virus enters the body. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Some people can be infected with the flu virus but have no symptoms. During this time, those people may still spread the virus to others.

Other than getting the flu vaccine, what else can I do to prevent the spread of the flu?

  • Hand hygiene (washing your hands with soap and water or an alcohol-based hand sanitizer) is a simple yet effective way to prevent the spread of infections, including influenza and COVID-19.
  • Social Distancing: Whenever possible, individuals should maintain a minimum safe “social distance” of six feet from others.
  • Avoiding those who are ill.
  • Covering your mouth and nose with a tissue when you cough or sneeze. Throwing the tissue in the trash after you use it. Coughing or sneezing into your elbow or shoulder, not into your hands, if you don’t have a tissue
  • Staying home if you are sick.
  • Keeping your children out of school if they are sick.

Are the influenza vaccines safe?
The following vaccines are in use and are extremely safe:

  • The inactivated (killed) virus vaccine, which is given by injection. This is safe for people older than 6 months. The common side effects are redness, tenderness and soreness at the vaccination site. You cannot get an infection from a killed virus, so this vaccine does not cause the flu. There are two main types of injected vaccine, one with protection against three strains of flu and one with protection against four strains. The CDC does not recommend one over the other, so whichever vaccine your doctor or pharmacy has in stock is okay to receive.
  • There is also a flu vaccine that uses no eggs, which makes it completely safe for patients who are allergic to eggs.

Keep in mind that all of the vaccine side effects are mild and resolve within one to two days of the administration of the vaccine. Also note: the injectable vaccine no longer contains thimerosal (mercury-containing compound) and the nasal vaccine never contained it. In rare cases, adults and children who receive the vaccine can have an allergic reaction.

Are the vaccines effective?
How well the flu vaccine works (or its ability to prevent flu illness) can range widely from season to season. The vaccine’s effectiveness also can vary depending on who is being vaccinated.

At least two factors play an important role in determining the likelihood that the flu vaccine will protect a person from flu illness: 1) characteristics of the person being vaccinated (such as their age and health), and 2) the similarity or “match” between the flu viruses the flu vaccine is designed to protect against and the flu viruses spreading in the community.

Recent studies show that flu vaccination reduces the risk of flu illness by between 40 and 60 percent among the overall population during seasons when there is a good match between circulating flu viruses and those in the flu vaccine. However, even during years when the vaccine match is very good, the benefits of vaccination will vary across the population, depending on characteristics of the person being vaccinated and even, potentially, which vaccine was used.

Each season, researchers try to determine how well flu vaccines work to regularly assess and confirm the value of flu vaccination as a public health intervention. Study results about how well a flu vaccine works can vary based on study design, outcome(s) measured, population studied and the season in which the flu vaccine was studied. These differences can make it difficult to compare one study’s results with another’s.

While determining how well a flu vaccine works is challenging, in general, recent studies have supported the conclusion that flu vaccination benefits public health, especially when the flu vaccine is well matched to circulating flu viruses.

Why should you get your influenza vaccine?
The CDC recommends that everyone over 6 months of age be vaccinated unless they have a known allergy to the flu vaccine. In addition, if you have a severe (life-threatening, with wheezing or throat narrowing) allergy to eggs or a history of Guillain-Barre syndrome (a neurologic disease) after a flu vaccine in the past, consult with your doctor before being vaccinated.

There are two main reasons to get vaccinated:

  • To protect yourself from the flu and its complications. The flu can cause five to seven days of illness with high fevers, painful muscle aches, cough, sore throat and exhaustion. People sick with the flu will miss work or school and need to be cared for. The flu also can lead to complications like pneumonia, which may require treatment with antibiotics or even hospitalization.
  • To protect those around you. Children less than 6 months old, who cannot be vaccinated yet, are at an increased risk of contracting the flu and are at a very high risk for complications. Vaccinating the parents of such children, and other adults and children around them, will help to protect them. There are other groups who either cannot be vaccinated or are at increased risk of complications from the flu, and by getting vaccinated, you help protect them further.

To find out where flu vaccines are offered in your area, call your doctor, pharmacy or other local health facility; or use the HealthMap Vaccine Finder.

*Source: cdc.gov/flu