Study on the Effect of Influenza Vaccination After Heart Attack on Future Cardiovascular Prognosis (IAMI)
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ClinicalTrials.gov Identifier: NCT02831608 |
Recruitment Status :
Completed
First Posted : July 13, 2016
Last Update Posted : September 22, 2021
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Background. For more than a century a causal link between influenza and cardiovascular disease has been suspected. It is conceivable that influenza may precipitate plaque rupture, increase cytokines with central roles in plaque destabilization and trigger the coagulation cascade. Accordingly, registry studies, case control studies and a few small randomized trials, all underpowered for clinical endpoints, have demonstrated that the risk for acute myocardial infarction (AMI) is increased following respiratory infection and that the risk of stroke and AMI in patients with established cardiovascular disease seem to be reduced following influenza vaccination. In May 2015 a Cochrane review concluded that influenza vaccination may reduce cardiovascular mortality and cardiovascular events but bias and inconsistent results in prior studies require higher-quality evidence to confirm these findings. High costs and little commercial interest in conducting a randomized trial on influenza vaccine in cardiovascular disease stand in the way.
Objective. The objective is to document whether influenza vaccination protects against cardiovascular events and death in patients with an AMI or very high risk stable coronary artery disease patients.
Methods. Population: 4400 patients with ST-elevation (STEMI), non-ST elevation myocardial infarction (NSTEMI) or very high risk stable coronary artery disease are randomized 1:1 in a blinded fashion using an RRCT design and followed up via registries and telephone calls. Intervention: Influenza vaccination. Control: Placebo (saline). Outcome: The primary endpoint is a composite of death, myocardial infarction and stent thrombosis till 1 year. Patients will be included in the study in all of Sweden's 7 university hospitals and 5 general hospitals, 4 university hospitals and 1 general hospital in Denmark, in 1 specialized heart center in Norway, 2 university hospitals in Czech Republic, 6 hospitals in Scotland, 1 university hospital in Latvia and 2 hospitals in Bangladesh. Secondary endpoints are time to all-cause death till 1 year, time to cardiovascular death till 1 year, time to stent thrombosis till 1 year, time to revascularization till 1 year, time to myocardial infarction till 1 year, time to cardiovascular death, a new myocardial infarction or stent thrombosis (first occurring) till 1 year, time to stroke, including TIA till 1 year, time to rehospitalization for heart failure till 1 year, time to hospitalization for arrhythmia till 1 year or length of hospital stay (if information is available). From a hypothesis generating perspective we aim to follow up patients through registries beyond 1 year and up to 5 years. The trial has been approved by the ethical committee system (Dnr 2014/264) and the Medical Products Agency (EudraCTnr -2014-001354-42) in Sweden.
Perspectives. If a clinical benefit can be demonstrated in this prospective trial influenza vaccination may become an important novel in-hospital therapy for patients with cardiovascular disease and the accompanying direct and indirect societal gains will be profound.
Condition or disease | Intervention/treatment | Phase |
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Myocardial Infarction Influenza, Human Influenza Vaccines Heart Failure Stroke | Biological: Influenza vaccine Biological: Placebo | Phase 4 |

Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 2571 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | Influenza Vaccination After Myocardial Infarction (IAMI Trial): A Multicenter, Prospective, Randomized Controlled Clinical Trial Based on National Angiography and Angioplasty Registries |
Study Start Date : | October 2016 |
Actual Primary Completion Date : | April 2021 |
Actual Study Completion Date : | August 2021 |

Arm | Intervention/treatment |
---|---|
Experimental: Drug: influenza vaccine
Standard influenza vaccine administered as a deep subcutaneous injection at one occasion per subject.
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Biological: Influenza vaccine
Other Name: Vaxigrip, Vaxigrip Tetra |
Placebo Comparator: Drug: placebo
Saline administered as a deep subcutaneous injection at one occasion per subject.
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Biological: Placebo |
- The number of participants with death, a new myocardial infarction or stent thrombosis (first occurring) according to ICD-10 codes. [ Time Frame: 1 year ]Composite endpoint of time to all-cause death, a new myocardial infarction or stent thrombosis (first occurring).
- The number of participants with stroke/transient ischemic attack according to ICD-10 codes. [ Time Frame: 1 year ]Time to stroke/transient ischemic attack will be registered.
- The number of participants with hospitalization for heart failure according to ICD-10 codes. [ Time Frame: 1 year ]Time to hospitalization for heart failure will be assessed.
- Length of hospital stay per participant. [ Time Frame: Pertains only to hospital stay at baseline. Realistic time frame: till 2 weeks ]Assessed by e-health records.
- The number of participants with: cardiovascular death, a new myocardial infarction or stent thrombosis assessed separately for each diagnosis according ICD-10 codes. [ Time Frame: 1 year ]Composite endpoint of cardiovascular death, a new myocardial infarction or stent thrombosis will be reported as separate secondary endpoints.
- The number of participants with: cardiovascular death according to ICD-10 codes. [ Time Frame: 1 year ]Cardiovascular death will be reported as a separate key secondary endpoint.
- The number of participants with a new revascularization [ Time Frame: 1 year ]Unplanned revascularization following the index hospitalization
- The number of participants with: death according to ICD-10 codes. [ Time Frame: 1 year ]Death will be reported as a separate key secondary endpoint.
- The number of participants with: a new myocardial infarction according to ICD-10 codes. [ Time Frame: 1 year ]New myocardial infarction will be reported as a separate key secondary endpoint.
- The number of participants with: stent thrombosis. [ Time Frame: 1 year ]Stent thrombosis will be reported as a separate key secondary endpoint.
- The number of participants with: arrhythmia according to ICD-10 codes. [ Time Frame: 1 year ]Arrhythmia will be reported as a separate secondary endpoint.
- The primary and secondary outcomes assessed beyond 1 year [ Time Frame: 5 years ]These outcomes will be considered exploratory only.

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Patients with a diagnosis of ST-elevation myocardial infarction (STEMI) or
- Patients with a diagnosis of non-STEMI or
- Patients with stable coronary artery disease ≥75 years of age undergoing angiography/PCI AND with at least one additional risk criterion
and
- A finalized coronary angiography/PCI (optional for sites in Bangladesh).
- Male or female subjects ≥18 years.
- Written informed consent.
Exclusion Criteria:
- Influenza vaccination during the current influenza season or anticipating to be vaccinated during the current influenza season.
- Indication for influenza vaccination for some indication other than myocardial infarction.
- Severe allergy to eggs or previous allergic reaction to influence vaccine.
- Suspicion of febrile illness or acute, ongoing infection.
- Hypersensitivity to the active substances or ingredients of Vaxigrip or against any residues, such as eggs (ovalbumin or chicken proteins), neomycin, formaldehyde and octoxinol.
- Subjects with endogenic or iatrogenic immunosuppression that may result in reduced immunization response.
- Inability to provide informed consent.
- Age below 18 years.
- Previous randomization in the IAMI trial.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02831608

Other Publications:
Responsible Party: | Ole Frobert, MD, PhD, MD, PhD, Region Örebro County |
ClinicalTrials.gov Identifier: | NCT02831608 |
Other Study ID Numbers: |
IAMI-2014 IAMI Trial ( Other Identifier: Regionorebrolan ) |
First Posted: | July 13, 2016 Key Record Dates |
Last Update Posted: | September 22, 2021 |
Last Verified: | September 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Influenza, Human Myocardial Infarction Infarction Heart Diseases Cardiovascular Diseases Respiratory Tract Infections Infections Orthomyxoviridae Infections |
RNA Virus Infections Virus Diseases Respiratory Tract Diseases Ischemia Pathologic Processes Necrosis Myocardial Ischemia Vascular Diseases |