Optimal Timing of COVID-19 Vaccination Following Acute Myocardial Infarction

H. Kerniss (Bremen)¹, P. Curman (Stockholm)², K. Kridin (Lübeck)³, S. Cremer (Frankfurt am Main)⁴, B. Kattih (Frankfurt am Main)⁴, M. Papathanasiou (Frankfurt am Main)⁴, R. J. Ludwig (Lübeck)⁵, D. Leistner (Frankfurt am Main)^4
1Bremer Institut für Herz- und Kreislaufforschung (BIHKF) Bremen, Deutschland; ²Dermato-Venereologica Clinic, Karolinska University Hospital, Stockholm, Sweden Stockholm, Schweden; ³Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck Lübeck, Deutschland; ⁴Universitätsklinikum Frankfurt Med. Klinik III - Kardiologie, Angiologie Frankfurt am Main, Deutschland; ⁵Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany Lübeck, Deutschland

 

Background:

For patients recovering from myocardial infarction (MI), the optimal timing of COVID-19 vaccination remains uncertain. Clinicians face the dilemma of whether to vaccinate early to ensure prompt protection or defer immunization to avoid potential transient pro-inflammatory or prothrombotic effects during the vulnerable post-infarction period. This study examined whether the timing of COVID-19 vaccination after MI is associated with major cardiovascular outcomes.

 

Methods:

Data were obtained from TriNetX, a global federated network of anonymized electronic health records used for large-scale real-world analyses. Patients hospitalized for acute MI who subsequently received an mRNA COVID-19 vaccine within one year included the analysis. Four mutually exclusive cohorts were defined by time from MI to first vaccine dose: ≤7 days (reference), 1 week–3 months, 3–6 months, and 6–12 months. Propensity-score matching (1:1) was applied to balance demographics, cardiometabolic risk factors, socioeconomic and psychosocial variables, and cardiovascular history (all post-match standardized mean differences <0.03). Outcomes were assessed up to 730 days. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE: all-cause death, recurrent MI, or ischemic stroke). Secondary endpoints included each MACCE component and atrial fibrillation/flutter.

 

Results:

A clear temporal gradient was observed, with progressively lower event hazards for later vaccination compared with ≤7 days post-MI. For MACCE, hazard ratios (HRs) were 0.57 (95% CI, 0.53–0.62; p<0.001) for 6–12 months, 0.62 (0.57–0.67; p<0.001) for 3–6 months, and 0.84 (0.78–0.90; p=0.007) for 1 week–3 months. Similar patterns were seen for all-cause mortality and recurrent MI. Ischemic stroke and atrial fibrillation risks were also lowest when vaccination occurred ≥3 months after MI, with no excess arrhythmic risk in any group.

 

Conclusions:

Compared with vaccination during the first week after MI, deferred COVID-19 vaccination was associated with progressively lower risks of MACCE, mortality, recurrent MI, and stroke. The most favorable window in these real-world data was 6–12 months post-MI, followed by 3–6 months. These findings support a deferred vaccination strategy—once clinical stability is achieved—preferably scheduling immunization ≥6 months after myocardial infarction.