Endothelial dysfunction detected after the second BNT162b2 mRNA COVID-19 vaccination was restored within six months

In this study, the Japanese authors used brachial arterial flow-mediated dilation (FMD) and nitroglycerin-induced vasodilation(NID), as markers for cardiovascular events, to investigate the effects of the BNT162b2 (BioNTech and Pfizer) mRNA COVID-19 vaccine on endothelial and vascular smooth muscle function. FMD is a high-resolution ultrasound assessment of endothelial function, whereas NID reflects the function of vascular smooth muscles. 

According to previous studies, FMD results are useful for predicting short-term cardiovascular events in a high-risk population, as well as long-term cardiovascular risk in a lower-risk population. In patients with atherosclerosis and coronary risk factors, prior studies have demonstrated diminished FMD values. Also, a decrease in FMD of 1% was associated with an increase in the risk of cardiovascular events of 10%. 

 

 

About the study

This single-center prospective study was conducted at Hiroshima University and involved 23 participants (16 men and 7 women). The mean age of the subjects was 36 years, ranging from 25 to 59 years. One subject had hypertension and two participants had dyslipidemia.ID-19

All subjects received two BNT162b2 mRNA COVID-19 vaccines (BioNTech and Pfizer). The FMD and NID were measured before, two weeks, and six months after the second vaccination. The subjects fasted overnight and abstained from smoking, drinking alcohol, and taking antioxidants, vitamins, and caffeine for at least 12 hours before the study. The participants were kept in a supine position, in a quiet, dark, and air-conditioned room throughout the study. The FMD and NID were measured after 30 minutes in the supine position.

 

Results

Two weeks after the second BNT162b2 mRNA COVID-19 vaccination, FMD values were reduced significantly compared to the pre-vaccination values. However, six months after the second COVID-19 vaccination, this difference was not present. Since FMD values have returned to their pre-vaccination baseline level, the authors concluded that impaired endothelial function after BNT162b2 mRNA vaccination was temporary.

Since NID values were similar before and after the vaccination, it appears that BNT162b2 vaccination did not impair the function of vascular smooth muscles.

 

Conclusion

Two weeks after the second BNT162b2 mRNA COVID-19 vaccination, brachial artery FMD assessment showed endothelial dysfunction in relatively healthy participants, which was restored within six months. According to NID values, the BNT162b2 vaccination did not impair the function of vascular smooth muscles.

The authors suggested that endothelial dysfunction detected after the second dose of the BNT162b2 vaccine, and restored within six months, may be related, at least in part, to thrombotic events that develop early after vaccination. Additionally, there is the possibility that the deleterious effect of the BNT162b2 vaccine on vascular function is more severe and prolonged in individuals with advanced atherosclerosis compared to healthy people.

This article was published in the Plos ONE.

 

 

Journal Reference

Yamaji T, Harada T, Hashimoto Y, Nakano Y, Kajikawa M, Yoshimura K, et al. Effects of BNT162b2 mRNA Covid-19 vaccine on vascular function. PLoS ONE 2024; 19(4): e0302512. https://doi.org/10.1371/journal.pone.0302512