Is there any harm in receiving two full dose flu vaccines one year?

It is generally not recommended to receive two full-dose flu vaccines in the same year as there is no evidence that it provides additional protection and there may be an increased risk of side effects. The Centers for Disease Control and Prevention (CDC) recommends that adults and children (6 months and older) get one annual flu vaccine every year, ideally before the end of October. If you missed the ideal timing, you can still get a flu vaccine as long as flu viruses are circulating in your community.

In some cases, a person may need to receive two flu vaccines if they are in a high-risk group and/or have a weakened immune system. For example, people who have undergone a stem cell transplant or are taking immunosuppressive medications may be advised to receive two doses of the flu vaccine to ensure adequate protection. However, this decision should be made in consultation with a healthcare professional.

If you accidentally receive two full-dose flu vaccines, it is important to monitor yourself for any side effects and report any concerns to your doctor. Common side effects of the flu vaccine include soreness, redness, or swelling at the injection site, as well as mild fever, chills, aches, fatigue, and headache. These symptoms typically go away within a few days.