Influenza (Flu)

Influenza, commonly called the “flu,” is a contagious virus that infects the nose, throat and sometimes the lungs. It can cause mild to severe illness and, at times, can lead to death. The best way to prevent flu is by getting a flu vaccine each year.

General Flu Information

Q When should you get vaccinated?


The best time to get vaccinated is before the flu season begins, which starts in October; however, a flu vaccination is recommended as long as it can still be beneficial throughout the year.

Q Who should get vaccinated?


Everyone six months of age and older should get a flu vaccine every year. Different flu shots are approved for people of different ages. Flu shots are approved for use in pregnant people and people with chronic health conditions.

Q Who should talk to their doctor before getting the flu shot?

  • People who have an allergy to eggs or other vaccine ingredients
  • People who have ever had Guillain-Barre Syndrome (GBS)
  • People who are feeling ill

Q Can a flu shot give you the flu?


No, a flu shot cannot cause flu illness. Flu vaccines are made either with flu vaccine viruses that are not infectious or with no flu viruses at all.

Q Is it better to get the flu than the flu vaccine?


No. Flu can be a serious disease, particularly among young children, older adults and people with certain chronic health conditions. Any flu infection can carry a risk of serious complications, hospitalization or death, even among healthy children and adults.

Q Do I really need a flu vaccine every year?


Yes. The Centers for Disease Control and Prevention recommends a yearly flu vaccine for just about everyone six months and older.

Q Should I wait to get vaccinated so that my immunity lasts through the end of the season?


It is recommended that flu vaccinations begin by October, if possible. However, as long as flu viruses are circulating, it is not too late to get vaccinated, even in January or later.

Flu Vaccine & Pregnant People

Q Should pregnant people get a flu shot?


Yes. If you’re pregnant, a flu shot:

  • is recommended at any time during your pregnancy
  • can reduce your risk of getting sick from flu
  • can protect your baby from flu for several months after birth

Q Why should pregnant people get a flu shot?


Flu is more likely to cause severe illness in pregnant people than in healthy people who are not pregnant. Changes in the immune system, heart and lungs during pregnancy make pregnant people (and people who have given birth during the past two weeks) more prone to severe illness from flu, including illness resulting in hospitalization. In addition, pregnant people pass antibodies on to the developing baby that will protect against flu for the first several months after birth.

Q Is it safe for pregnant people and their developing babies to get a flu shot?


Yes. Pregnant people can get a flu shot during any trimester of their pregnancy to protect themselves and their newborn babies from flu. The nasal spray vaccine is not recommended for pregnant people.

Q Can flu vaccination result in miscarriage?


Multiple studies have shown that patients who have gotten flu shots during pregnancy have not had a higher risk for miscarriages. Talk to your doctor if you have concerns about vaccination during pregnancy.

Q What side effects have pregnant people experienced from flu shots?


The most common side effects experienced by pregnant people are the same as those experienced by other people. They are generally mild and include:

  • Soreness, redness and/or swelling from the shot
  • Fainting
  • Headache
  • Fever
  • Muscle aches
  • Nausea
  • Fatigue

*If side effects occur, they usually begin soon after the shot is given and generally last for one to two days.

Flu Vaccine & High-Risk Patients

Q What is a high-risk patient?


Most people who get the flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of the flu, which can be life-threatening.

Serious problems related to the flu can happen at any age, but some people are at high-risk of developing serious flu-related complications if they get sick. This includes people 65 years and older, people of any age with certain chronic medical conditions (such as asthma, diabetes or heart disease), pregnant women and young children.

Q Who is at high risk from flu?

  • Children younger than five, but especially children younger than two years old
  • Adults 65 years of age and older
  • Pregnant people (and people up to two weeks postpartum)
  • Residents of nursing homes and other long-term care facilities
  • American Indians and Alaska Natives

Q What chronic health problems increase the risk of serious flu-related complications?

  • Asthma
  • Neurological and neurodevelopmental conditions (including disorders of the brain, spinal cord, peripheral nerve and muscle such as cerebral palsy, epilepsy, stroke, intellectual disability, 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)
  • 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/AIDS, cancer or those on chronic steroids)
  • People younger than 19 who are receiving long-term aspirin therapy
  • People with extreme obesity

Q What are the emergency warning signs of flu sickness in children?

  • Fast 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

Seek immediate medical help for an infant who has any of the following:

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

Q What are the emergency warning signs of flu sickness in adults?

  • 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


Centers for Disease Control and Prevention. (2018, September 17). Pregnant Women & Influenza (Flu). Retrieved from

Centers for Disease Control and Prevention. (2018, August 27). People at High Risk of Developing Serious Flu-Related Complications. Retrieved from