COVID AND THE VACCINE - TRUTH, LIES, AND MISCONCEPTIONS REVEALED, page-98968

As researchers study links between COVID-19 vaccines and uncommon side effects, they have found a slight increase in the number of people who have experienced postural orthostatic tachycardia syndrome (POTS) following vaccination. However, this association is five times less common compared to people who developed POTS after having COVID. The findings from this study, which was partially supported by NHLBI, published in Nature Cardiovascular Researchexternal link.

Researchers study links between COVID and POTS | NHLBI, NIH