Diabetes during flu season: 5 answers about the flu shot

A look at the benefits of getting a flu shot, the common side effects, and what to ask your healthcare provider.

A healthcare provider administers a flu shot into the upper arm of a male patient during a healthcare appointment.

Updated on November 8, 2024.

The flu is a respiratory infection caused by an influenza virus. Though influenza viruses spread year-round, the highest number of cases occur during the fall and winter months (with the greatest number typically occurring between December and February). This time of year is referred to as “flu season.”

The Centers for Disease Control and Prevention recommend that nearly everyone—children over 6 months and adults at every age—get vaccinated against the flu. Influenza vaccines are commonly referred to as “flu shots.”

While influenza vaccination is recommended for nearly everyone, flu shots are considered even more important for people who are at greater risk for flu complications. This includes people who are living with a chronic health condition, including people who are living with any form of diabetes.

What are the benefits of getting a flu shot?

Getting a flu shot can prevent a person from becoming infected with influenza. It also helps reduce the severity of symptoms if a person does become infected.

This can make a major difference in a person who has diabetes. Having diabetes weakens the immune system. This means the immune system is overall less effective at fighting infections like the flu.

Flu-related complications include:

  • Pneumonia, a serious and potentially life-threatening lung infection
  • Cardiovascular events like heart attack and stroke
  • Sepsis, an extreme overreaction by the immune system that can cause organ failure and death

Vaccination has been shown to prevent flu-related complications among people with diabetes.

Becoming sick with the flu is also associated with worse diabetes control. The immune response that occurs when the body fights an infection can increase blood glucose levels. Flu symptoms can make it difficult to eat normally, which can put a person at increased risk for episodes of very low blood glucose (hypoglycemia).

What are the risks of getting the flu shot?

Flu shots generally cause mild, short-term side effects. A common side effect is redness, soreness, or irritation at the site of injection. Other common side effects are headache, fever, muscle ache, nausea, and/or fatigue. Mild side effects from a vaccine are not the same as being sick—and are actually a sign that the immune system is responding to the vaccine.

Flu vaccines rarely cause serious side effects. Before receiving any vaccine, it’s important to tell your healthcare provider and/or pharmacist about:

  • Any known allergies and any history of allergic reactions.
  • Any and all medications you take. This list should include prescription medications, over-the-counter medications, and supplements (including herbal supplements).
  • Your medical history, including any medical conditions or medical problems that you are currently managing and any you have been diagnosed with in the past.

When is the best time to get a flu shot?

This is a good question to ask your healthcare provider and/or pharmacist. The Centers for Disease Control and Prevention recommends that everyone be vaccinated by the end of October—but getting vaccinated later is a much better option than not getting vaccinated at all.

Why do you need a new flu shot every year?

Influenza viruses are constantly changing, Likewise, flu shots need to change. Each year, new flu shots are needed to protect against new strains of influenza virus. The effectiveness of flu shots may decrease over time, so a flu shot a person received the previous flu season will have lost its effectiveness.

What flu shot should you get?

This is a question that is best answered by a healthcare provider and/or pharmacist. There are multiple types of flu vaccines available, and different vaccines may be recommended based on age, existing medical conditions, and other factors:

  • People with diabetes and other chronic health conditions are advised to get an injectable vaccine. Vaccines that are administered as injections do not contain any live virus.
  • The flu vaccine that is available as a nasal spray does contain a live (though extremely weakened) virus, and it is not the preferred choice for people with chronic health conditions or people who are pregnant.
  • Enhanced (high-dose) inactivated vaccines are preferred for people 65 and older. Several options are available. These vaccines are designed to boost immune response and offer more protection for people who are at a greater risk of flu complications.

For questions about the flu or flu vaccine, your best source of information will be your healthcare provider or pharmacist.

Article sources open article sources

MedlinePlus Medical Encyclopedia. Flu.
Centers for Disease Control and Prevention. Flu Season.
Centers for Disease Control and Prevention. Who Needs a Flu Vaccine.
Mayo Clinic. Flu shot: Your best bet for avoiding influenza.
Centers for Disease Control and Prevention. People at Increased Risk for Flu Complications.
Swapna Thomas, Allal Ouhtit, et al. Burden and disease pathogenesis of influenza and other respiratory viruses in diabetic patients. Journal of Infection and Public Health, 2022. Volume 15, No. 4.
Sandrine I. Samson, Kevin Konty, et al. Quantifying the Impact of Influenza Among Persons With Type 2 Diabetes Mellitus: A New Approach to Determine Medical and Physical Activity Impact. Journal of Diabetes Science and Technology, 2019. Vol. 20, No. 15.
Centers for Disease Control and Prevention. About Sepsis.
Centers for Disease Control and Prevention. Your Immune System and Diabetes.
American Diabetes Association. Planning for Sick Days.
MedlinePlus. Hypoglycemia.
Centers for Disease Control and Prevention. Key Facts About Seasonal Flu Vaccine.
National Heart, Lung, and Blood Institute. Vaccine side effects signal their effectiveness. November 30, 2022.
Mayo Clinic. Influenza virus vaccine (intradermal route, intramuscular route).
Anthony L. Komaroff. Why do we need new flu shots every year? Harvard Health Publishing. April 23, 2023.
Centers for Disease Control and Prevention. Different Types of Flu Vaccines.
Centers for Disease Control and Prevention. Live Attenuated Influenza Vaccine [LAIV] (The Nasal Spray Flu Vaccine).
Pritish K. Tosh. How are high-dose flu vaccines different from other flu vaccines? October 1, 2024.

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