Detailed Description:
Name of investigational treatment: Influenza vaccine ("Ultrix Quadri"™) Planned study period: October - December 2021 ((influenza season) Long-term follow up to 365 days from the moment of vaccination of the last included patient (approximately November-December 2022) via phone calls.
Methodology: vaccination will be start after informed consent on the day of leaving hospital with "Ultrix Quadri"™ vaccine Intervention Model: Parallel Assignment Number of subjects: 400 Number of vaccinated patients is 200 Number of patients with placebo is 200 Primary endpoint: сomposite of all-cause death, MI, or stent thrombosis at 12 months Secondary endpoints
* The number of participants with all-cause death till 1 year (key secondary outcome)
* The number of participants with myocardial infarction till 1 year (key secondary outcome)
* The number of participants with stent thrombosis till 1 year (key secondary outcome)
* The number of participants with cardiovascular death till 1 year (key secondary outcome)
* The number of participants with a new revascularization till 1 year
* The number of participants with cardiovascular death, a new myocardial infarction or stent thrombosis (first occurring) till 1 year
* The number of participants with stroke, including transient ischemic attack (TIA) till 1 year
* The number of participants with hospitalization for heart failure till 1 year
* The number of participants with hospitalization for arrhythmia till 1 year
* Safety of vaccination (incidence of side effects)
Follow up by telephone and registry information (AIS "Mortality"): the follow up for endpoints will be performed using telephone contacts with the patients or first degree relatives.
Purpose of phone calls:
* to assess the safety of vaccination the day after vaccination (T1) 7 (± 1) day after vaccination (T2)
* to study the effectiveness 365 (± 5) days after vaccination (T3)
Reporting for adverse events: The patients will be informed to contact the investigator or study nurse if any adverse event should occur during this timeframe.
Study Start Date: September 2021 Actual Primary Completion Date (safety assessment): December 2021 Actual Study Completion Date (efficiency mark): December 2022 Experimental Drug: influenza vaccine Ultrix Quadri Standard influenza vaccine administered as a deep subcutaneous injection at one occasion per subject.
The experimental drug is not administered to patients in the control group.
Eligibility Criteria:
Ages Eligible for Study: 65 Years and older (Adult, Older Adult) Sexes Eligible for Study: All
Inclusion Criteria:
* Patients with a diagnosis of ACS with transformation to acute MI or unstable angina Patients with a diagnosis of Chronic Heart Failure due to different reasons
* Written informed consent.
Exclusion Criteria:
* Influenza vaccination during the current influenza season or anticipating to be vaccinated during the current influenza season.
* Coronavirus disease 2019 vaccination during 30 days
* 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 Ultrix Quadri 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 65 years.
