Who should get a flu vaccine?

Those considered high-risk for the flu should be vaccinated at the start of every flu season. The Centers for Disease Control and Prevention (CDC) recommends all children ages 6 to 23 months get the flu shot. Very young children are more likely than older children and adults to be hospitalized and to die from the flu. Infants under 6 months are too young to take the vaccine safely, therefore all the people around them (child care workers and family) should be vaccinated.

Older adults (65 and up) should be vaccinated, as should anyone with chronic health conditions, including asthma and diabetes. The CDC also recommends pregnant women and health care workers receive the vaccination.

Do not give the flu shot to:

  • Those who have had a severe reaction to the flu shot in the past
  • Those who developed the rare nerve disease Guillain-Barre Syndrome, within six weeks of a previous flu shot
  • Anyone who is running a fever
  • Infants under 6 months of age
  • Anyone allergic to chicken eggs (the flu vaccine is grown in eggs)

Many people complain of mild flu-like symptoms, including muscle aches, low-grade fever and tiredness, but severe side effects are rare. Side effects usually begin within a few hours of getting the shot. They usually last for about two days.

If you have children under age 9, who have never had flu shots, it becomes especially important to get an early start. They need two vaccinations about one month apart.

The earlier you get vaccinated the better. It takes about two weeks before the vaccine takes full protective effect.

The vaccine comes in two forms: a nasal spray or a shot. It works by triggering the body's immune system response. After the vaccination, your body will recognize the flu virus as a foreign invader and will produces antibodies to fight it. Then, the next time your body encounters the flu virus, it remembers the virus is a hostile invader and quickly launches an immune attack to kill it.

If your body does remember the virus, why is it important to get a flu shot every year? First, because strains of flu differ from year to year; second, immunity declines over time.

Vaccines, which are made with killed or inactivated virus or viral fragments of those strains, work by forcing the immune system to make antibodies that fight circulating strains of influenza. Because flu can be so serious and can spread so rapidly, the Centers for Disease Control and Prevention (CDC) recommends that everyone age six months and older get vaccinated every year. A yearly flu vaccine is the first and most important step in protecting against flu, according to the CDC.

Vaccines are especially important to those most susceptible to flu complications, including older people, children, pregnant women, people who are morbidly obese, people with compromised immune systems and those with chronic illnesses such as heart disease, kidney disease, asthma, chronic obstructive pulmonary disease (COPD) and diabetes. Certain groups also need to get vaccinated because they are at risk for serious flu-related complications or they live with or care for people at risk for developing these complications. These groups include:

  • Pregnant women
  • Children younger than age five, but especially children younger than two
  • People age 65 or over
  • Anyone with chronic medical conditions, especially asthma or chronic bronchitis and emphysema
  • Anyone in a long-term care facility or nursing home
  • Anyone who lives with or cares for those at high risk of complications from flu, including healthcare workers; household contacts and out-of-home caregivers of children younger than six months; and people within regular contact with those at risk for flu complications

Everyone six months of age or older should receive the flu vaccine each year. If you have a baby younger than six months of age, you can protect him from catching the flu by vaccinating everyone else in your house. Some children under age 9 need two doses of the flu vaccine at least 4 weeks apart, especially if this is the first year your child is receiving the flu vaccine.

Pregnant women are at a higher risk of having complications if they catch the flu so if you are pregnant, ask your OB for a flu shot right away. Breastfeeding women can get either the inactivated flu shot or the live-virus nasal spray vaccine. Nursing women will help protect their baby from catching the flu by breastfeeding and getting vaccinated.

In addition to the flu vaccine, remember to wash your hands, cover your cough and stay home if you are sick.

People who are at the highest risk of developing complications from the flu are those who are elderly or who have certain chronic (long-term) medical conditions. Even if you don't fit that description, you may still want to get an annual influenza vaccine. The vaccine will be 70 to 80 percent effective in preventing the flu or reducing its severity. The influenza vaccine is given in the fall, so that antibodies (protective proteins of the immune system) can build up for the peak flu months of November through March.

Dr. Bonnie Lynn Wright, PhD
Geriatrics Nursing Specialist

The age requirement for flu vaccine varies. In Canada, many provinces and territories recommend universal influenza immunization. The Public Health Agency of Canada's website will have specific information about provincial requirements and the effectiveness of universal immunization.

Continue Learning about Vaccine

Hawaii Health Alert: Why You Probably Need the Tdap Shot
Hawaii Health Alert: Why You Probably Need the Tdap Shot
You put in the extra effort to keep your kids and grandkids healthy—you make sure they get nutritious meals, safe toys and regular checkups. But the g...
Read More
Dr. Diane Harper - How long do human papillomavirus (HPV) vaccines protect against infection?
Dr. Diane Harper - How long do human papillomavirus (HPV) vaccines protect against infection?
Dr. Robin Miller, Where Do You Stand In the Vaccine Debate?
Dr. Robin Miller, Where Do You Stand In the Vaccine Debate?
Dr. Diane Harper - How do I protect myself from human papillomavirus (HPV)?
Dr. Diane Harper - How do I protect myself from human papillomavirus (HPV)?

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.