Cardiovascular Risks Post-COVID-19 Vaccine: Key Insights

A recent European Heart Journal study employed data from a Swedish countrywide register-based cohort to examine the risks of cardiovascular and cerebrovascular events following immunization against the coronavirus illness 2019 (COVID-19).

The COVID-19 vaccine’s risks
The COVID-19 messenger ribonucleic acid (mRNA) vaccination has the potential to raise the risk of myocarditis and pericarditis, among other cardiovascular problems, albeit being extremely rare. Within two weeks of vaccination, especially after the second dosage, young males have shown the highest incidence of these occurrences.

Those who received the vaccination had a low incidence of myocardial infarction (MI), according to clinical trials carried out by Pfizer and Moderna. Studies on population-based acute MI occurrences after immunization are still lacking, nevertheless.

The risk of atrial fibrillation (AF) is very low, whereas the COVID-19 immunization does not appear to raise the risk of MI, according to the available data. Moreover, research at the individual level has not indicated a higher incidence of stroke following immunization.

However, more research is required to ascertain whether COVID-19 mRNA vaccinations raise the risk of consequences unrelated to cardiovascular health, such as pericarditis and myocarditis.

About the Study

The current study’s researchers postulated that the same mechanism that raises the risks of myocarditis and pericarditis in young people may also have a role in the development of other harmful cardiovascular events in different age groups and with varied time lags. In order to evaluate the risks of various cardiovascular and cerebrovascular events, a variety of risk windows and doses were taken into consideration.

Between December 29, 2020, and December 31, 2022, patient data were collected. Following each immunization dosage, the risk of dysrhythmias, myocarditis/pericarditis, heart failure (HF), cerebrovascular events such as stroke and transient ischemic attack, and MI was evaluated over a range of risk windows.

Calculated risk ratios (HRs) with 95% confidence intervals were compared to those who had not received a vaccination. HRs were calculated using Cox regression models that were confounded factor-adjusted.

Results of the trial:

Of the 8,070,674 people in the trial cohort, 88.5% had at least one dose of the mRNA COVID-19 vaccination, 86.9% had at least two doses, and 67.9% had three or more doses. The dose-receiving individuals were marginally older. Prescription antidepressant-treated illnesses and hypertension were the two most prevalent medical disorders.

Following the first two immunization doses, there was an elevated early risk of both myocarditis and pericarditis, with a larger effect size for myocarditis. In both cases, the dose and time window patterns were comparable.

These two diseases were merged as myopericarditis in the main analysis; its elevated risk was first noted in the first week following dosage one and continued into the second week. The risk increased in the first week following the second dosage, but no effect was seen following the third. The risk estimate was larger for males between the ages of 18 and 40, and the danger was more noticeable after receiving the Moderna mRNA-1273 vaccine than it was the Pfizer BNT162b2 vaccine.

There was an increased chance of extrasystoles between the first and second dosages. This effect was more pronounced in men and the elderly, but there was no clear window of time for it.

All risk windows showed reduced chances for arrhythmias, especially after the third dose. There was no discernible difference between the Pfizer and Moderna vaccinations, and both sexes were linked to comparable risk profiles.

Following immunization, there was a decreased incidence of MI and HF, especially in the oldest groups and after the third dosage. There was no discernible variation in the risk patterns between the sexes for any of the vaccinations.

Transient ischemic attacks (TIAs) were shown to be more common following the second vaccination dose, especially in later risk windows. TIA was infrequently experienced by people 40 years of age and younger after vaccination. These effects rose with age and were consistent across sexes and vaccination histories.

In terms of ischemic and hemorrhagic stroke, the risks were similar for all ages, sexes, and vaccination types, especially after the third dosage. After the third dose, there was a decreased risk for the composite of TIA or stroke.

In conclusion
In a cohort of Swedish individuals, the current study indicates lower chances of numerous major cardiovascular events after COVID-19 vaccination. This reduction may be due to the vaccine’s ability to protect against severe disease. However, following COVID-19 mRNA vaccination, a higher risk of extrasystoles, TIA, myocarditis, and pericarditis was noted.

When combined, these results demonstrate the prophylactic advantages of a full COVID-19 immunization, especially for older individuals.

For more information: Cardiovascular events following coronavirus disease 2019 vaccination in adults: A nationwide Swedish study, European Heart Journal, https://doi.org/10.1093/eurheartj/ehae639