What is the Vaccine?


The high dose and standard dose flu vaccines, called Fluzone®, are approved by the Food and Drug Administration. Both vaccines protect against infection caused by influenza A and influenza B viruses. The high dose is not approved for adults under 65; in this age group, its use is investigational.

Who Will Be Enrolled?


INVESTED will enroll individuals with a history of a heart attack within one year or a hospitalization for heart failure within 2 years, and one other risk factor. Individuals who have already received a flu shot this season are not eligible for enrollment. 


What Is Involved to Start?

  • Signing Informed Consent

  • Completing a study visit to make sure you are eligible to participate

  • Randomly receiving, like a flip of the coin, either the standard dose or high dose by a shot given in the arm

  • Allowing study staff to have information from your medical history about your heart disease and current medications

  • Providing demographic and contact information for telephone follow-up

  • Completing a symptoms diary for one week following the flu shot

Will This Cost Me Anything?

There is no cost to participate in this study.


What Are the Potential Benefits?

Research findings based on INVESTED may benefit future individuals by helping us understand whether a high dose or standard dose influenza “flu” vaccine is better for those with heart disease.



What Else Is Involved?

  • Initial contact one week after your vaccination, to ask if you had any reactions or symptoms to the vaccine.

  • Two phone calls

    • End of the flu season (May)

    • During the summer (July or August) to ask if you are interested in remaining in the study for another flu season.

  • To better assess the benefit of the vaccine, we are hoping that you will be able to participate in the study for 3 years. This would involve completing one study visit to receive the vaccine each year (up to 3 years) with telephone follow-up three times per year (up to 3 years).

  • Optional participation in the immune response sub-study, which would involve a blood draw at the initial visit followed by a blood draw four weeks later. 

  • You will not have to stop taking any medications in order to participate.

Do I Have to Participate?

You do not have to participate in this study! It’s completely up to you. You may receive the flu vaccine without participating in the study.

Are There Any Risks in Participating?

  • Mild soreness at the injection site, headache, and muscle aches are the most commonly reported symptoms following the flu vaccine.

  • With any vaccine, there is a slight risk of severe allergic reaction.

  • As with all clinical trials, there is a slight risk of a loss of confidentiality.