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Flu: What you need to know

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​​​​Contact any Marshfield Clinic Health System location for information on how to get your flu shot.

Click below to learn more about influenza, including its symptoms and treatments. 



What is the flu?

Influenza is commonly referred to as “the flu.” Influenza itself is a broad term for several types of contagious upper respiratory infections caused by different viruses. Influenza viruses can cause infection of the nose, throat and lungs. Each year, seasonal strains of virus cause outbreaks of the infection.

Influenza usually spreads from person to person when someone infected coughs, sneezes or talks and expels the virus into the air. You also can contract the virus by handling an object touched by an infected person.

People can be contagious with influenza a day before symptoms show, which makes it so easy to spread the illness from one person to another.

Influenza may cause symptoms ranging from mild to life threatening. Every year in the United States, and estimated 9 million – 45 million people become ill from influenza; between 140,000 and 810,000 people are hospitalized from influenza-related complications, and; between 12,000 and 61,000 deaths are reported from influenza-related causes, according to the Centers for Disease Control and Prevention (CDC).

What are the symptoms of flu?

Symptoms of influenza include:

  • Fever* (102-103° F).
  • Cough.
  • Sore throat.
  • Runny or stuffy nose.
  • Body aches.
  • Headache.
  • Chills.
  • Fatigue.
  • Sometimes diarrhea and vomiting.

*It's important to note that not everyone with flu will have a fever.

The seasonal influenza virus usually changes or mutates every year. Because of this change, a new vaccine is required each year to prevent the disease. A flu shot is your best defense against influenza.

Note: Influenza and COVID-19 are both contagious respiratory illnesses caused by different viruses. Because some of the symptoms of influenza and COVID-19 are similar, it may be hard to tell the difference between them, and testing may be needed to help confirm a diagnosis. Contact your primary care provider if you have flu-like symptoms to learn the best treatment for you.

Who should be vaccinated for the flu?

Vaccinations are the most important line of defense against influenza (the flu).

Seasonal flu shots are normally very effective in preventing that strain of influenza.

Because the virus strains that cause influenza change from year to year, it is important for most people to receive a vaccination every year. The Centers for Disease Control and Prevention (CDC) recommend the following groups be vaccinated.

Vaccination recommendations for influenza

  • Annual vaccination is recommended for people ages 6 months and older.
  • Children 6 months - 8 years who did not receive two or more seasonal influenza doses since July 2020 will need two doses this influenza season.
  • Everyone who wants to reduce the risk of becoming sick with influenza or passing it on to others should be vaccinated.

People who have medical conditions

People with the following medical conditions are at a higher risk for influenza-related complications:

  • Asthma
  • Neurological and neurodevelopmental conditions [including disorders of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy (seizure disorders), stroke, intellectual disability (mental retardation), moderate to severe developmental delay, muscular dystrophy, or spinal cord injury]
  • Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
  • Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)
  • Blood disorders (such as sickle cell disease)
  • Endocrine disorders (such as diabetes mellitus)
  • Kidney disorders
  • Liver disorders
  • Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
  • Weakened immune system due to disease or medication (such as people with HIV or AIDS, or cancer, or those on chronic steroids)
  • People younger than 19 years of age who are receiving long-term aspirin therapy
  • People with Chronic Obstructive Pulmonary Disease (COPD)
  • People who are morbidly obese (Body Mass Index, or BMI, of 40 or greater)

Who should not be vaccinated with the flu shot?

There are some people who should not get a flu vaccine without first consulting a health care provider These include:

  • Children less than 6 months of age.
  • People with severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine.*
  • People who have ever had Guillain-Barré syndrome (GBS).
  • People who have a moderate-to-severe illness (they should talk to their doctor about their symptoms first).

*People with egg allergies no longer need to be observed for an allergic reaction for 30 minutes after receiving their flu shot. People with a history of egg allergy of any severity should receive any licensed, recommended, and age-appropriate influenza vaccine. For more information on influenza vaccine and egg allergies, visit CDC webpage.

Your health care provider can help you decide whether vaccination is right for you, and select the best vaccine for your situation.

It takes about two weeks after you receive the shot to develop immunity.

There are few side effects for most persons receiving flu shots. These may include a sore arm where the shot was administered, a slight fever or body aches.

In most cases, the side effects only last a few days. If you develop more severe reactions, contact your health care provider immediately.

How is the flu treated?

If you become ill with influenza, the CDC recommends:

  • Stay home from work or school
  • Avoid contact with others except to get medical care.
  • Get lots of rest
  • Drink plenty of liquids
  • Avoid using alcohol and tobacco

Note: Influenza and COVID-19 are both contagious respiratory illnesses caused by different viruses. Because some of the symptoms of influenza and COVID-19 are similar, it may be hard to tell the difference between them, and testing may be needed to help confirm a diagnosis. Contact your primary care provider if you have flu-like symptoms to learn the best treatment for you.

There are over-the-counter (OTC) medications to relieve the symptoms of influenza (but never give aspirin to children or teenagers who have influenza-like symptoms, particularly fever). Remember that serious illness from influenza is more likely in certain groups of people, including people 65 and older, pregnant women, people with certain chronic medical conditions and young children.

Be aware of emergency warning signs that require urgent medical attention.

Care for children

Children, especially very young children may be more susceptible to severe complications of seasonal influenza.

Influenza can be a serious medical condition for younger children. According to the Centers for Disease Control and Prevention (CDC):

Children commonly need medical care because of influenza, especially before they turn 5 years old. Severe influenza complications are most common in children younger than 2 years old. Children with chronic health problems like asthma and diabetes are at especially high risk of developing serious influenza complications.

Children younger than 6 months of age

Children younger the 6 months of age are not approved to be vaccinated against influenza, so they are particularly vulnerable to influenza and its complications.

The best protection for children this young is for caregivers (both in and outside the home) to be vaccinated against seasonal influenza.

Children from age 6 months to 5 years old

The CDC notes that this age group is in danger of contracting influenza and may suffer serious consequences.

According to the CDC, more than 20,000 children younger than 5 years old are hospitalized because of influenza. Even children in this age group who are otherwise healthy are at risk simply because of their age.

To protect their health, all children 6 months and older should be vaccinated against influenza each year. Vaccinating young children, their families and other caregivers early in the influenza season – September or October – can help protect them from getting sick.

Children with chronic medical conditions may need special care in avoiding or treating influenza.

Care for seniors

Anyone 65 years and older are at high risk for serious complications from influenza.

According to the CDC, 90 percent of seasonal influenza deaths and more than half of hospitalizations occur in people 65 years and older each year.

The most important step is to get a vaccination for the seasonal influenza each year early in the fall. Even if you aren't vaccinated early, it is still important to get the flu shot because you are at risk for the seasonal influenza through spring.

Others at risk

If you have a chronic medical condition such as heart disease, diabetes and so on, you may be at even greater risk for serious complications from influenza. Consult your doctor and take the recommended steps to care for yourself.

Emergency symptoms

You should be aware of symptoms that signal a medical emergency.

In children, emergency warning signs that need urgent medical attention include:

  • Fast breathing or trouble breathing
  • Bluish skin color
  • Not drinking enough fluids
  • Not waking up or not interacting
  • Being so irritable that the child does not want to be held
  • Flu-like symptoms improve but then return with fever and worse cough
  • Fever with a rash

In addition to the signs above, get medical help right away for any infant who has any of these signs:

  • Being unable to eat
  • Has trouble breathing
  • Has no tears when crying
  • Significantly fewer wet diapers than normal

In adults, emergency warning signs that need urgent medical attention include:

  • Difficulty breathing or shortness of breath
  • Pain or pressure in the chest or abdomen
  • Sudden dizziness
  • Confusion
  • Severe or persistent vomiting
  • Flu-like symptoms that improve but then return with fever and worse cough

Seek emergency medical care if you or someone you know is experiencing any of the emergency symptoms above.

How can the flu be prevented?

Marshfield Clinic Health System recommends you take the following precautions to protect yourself, your family and your community from influenza.

Preventive steps

  • Getting a flu shot is the most important way to protect yourself, your family and your community.
  • Avoid close contact with someone who is sick, if possible.
  • Cover your mouth and nose with a face covering when in public.
  • Cover your mouth and nose with a tissue if you sneeze or cough, throw away the tissue and wash your hands.
  • You can get influenza by touching an object that has been handled by a person with influenza. Use sanitizing wipes to help disinfect objects that may pass the influenza virus.
  • Thoroughly washing your hands with warm water and soap or use an alcohol-base hand disinfectant to help you stay healthy.
  • Avoid putting your hands near your eyes, nose or mouth.
  • If you become sick with flu-like symptoms, stay home from work and public places to prevent spreading influenza. Note: Because some of the symptoms of influenza and COVID-19 are similar, it may be hard to tell the difference between them, and testing may be needed to help confirm a diagnosis. Contact your primary care provider if you have flu-like symptoms to learn the best options for you.

A care plan with you in mind

Marshfield Clinic Health System is prepared to help you prevent influenza by offering flu vaccination clinics throughout Wisconsin. If you get sick, we will care for you.

Marshfield Laboratories has the expertise to quickly identify viruses that cause respiratory illness. 

Our providers and staff are working tirelessly to ensure that your safety is always our top priority. We continue to update the way we deliver care based on the latest guidelines from the Centers for Disease Control and Prevention (CDC). Click here to learn more about the steps we are taking to keep patients safe throughout their health journey.

How can you avoid getting the flu at work?

Influenza (flu) is a highly contagious disease easily spread where people gather, such as the workplace.

Consider these important steps you can take to protect yourself and others at work:

  • Wash your hands often with soap and water for 20 seconds, or use an alcohol-based hand sanitizer if soap and water are not available. Be sure to wash your hands after coughing, sneezing or blowing your nose.
  • Avoid touching your nose, mouth and eyes. Germs spread this way.
  • Cover your nose and mouth with a face covering when in public, and cover coughs and sneezes with a tissue. Dispose of tissues in no-touch trash receptacles. Wash your hands after disposing of soiled tissues.
  • Keep frequently touched common surfaces clean, such as telephones, computer keyboards, doorknobs, etc.
  • Do not use other workers' phones, desks, offices or other work tools and equipment. If you need to use a coworker's phone, desk or other equipment, clean it first.
  • Don't spread influenza! If you are sick with flu-like illness, stay home. Symptoms of influenza  can include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, tiredness and sometimes vomiting and diarrhea.* If supervisors or employees have questions about use of leave for illness or to care for an ill family member, please contact your local Human Resources office or your office's leave administrator.
  • Get vaccinated against seasonal flu.
  • Maintain a healthy lifestyle through rest, diet and exercise.

*Note: Influenza and COVID-19 are both contagious respiratory illnesses caused by different viruses. Because some of the symptoms of influenza and COVID-19 are similar, it may be hard to tell the difference between them, and testing may be needed to help confirm a diagnosis. Contact your primary care provider if you have flu-like symptoms to learn the best treatment for you.

Employers can help limit the spread of influenza in the workplace by considering on-site vaccinations for their staff. A number of health care providers, including Marshfield Clinic Health System, offer on-site flu vaccinations.

Learn more. Visit Centers for Disease Control and Prevention  or call 1-800-CDC-INFO (232-4636).

TTY: 888-232-6348

Email: cdcinfo@cdc.gov

​Pregnant women and the flu

Pregnant women, even ones who are healthy, can have medical complications from seasonal influenza.

Click here for more


High-risk groups for flu complications

Influenza (flu) viruses can infect anyone, but some groups of people are more at risk for serious complications than others.

Click here for more


Flu symptoms include:

Fever* (102-103° F)

Cough

Sore throat

Runny or stuffy nose

Body aches

Headache

Chills

Fatigue

Sometimes diarrhea and vomiting

*It's important to note that not everyone with influenza will have a fever.

Note: Because some of the symptoms of influenza and COVID-19 are similar, it may be hard to tell the difference between them, and testing may be needed to help confirm a diagnosis. Contact your primary care provider if you have flu-like symptoms to learn the best treatment for you


  Get your flu shot  


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Additional Resources

Centers for Disease Control and Prevention

World Health Organization

Center for Infectious Disease Research & Policy (CIDRAP): Pandemic Influenza Update

State of Wisconsin Pandemic Web Site

Flu Webpage Right Rail