I received my booster shot (3rd Moderna COVID-19 vaccine) on November 17. I understand that correlation is not causation, but in the interest of reporting a possible involvement between the vaccine and my health situation, I wanted to report that on November 30 I was admitted to the cardiac ICU with myopericarditis with pericardial effusion. A medical procedure and subsequent pericardial drain removed 900 mL of extra fluid from my pericardium, and I was in the cardiac ICU for 9 days, moved to the cardiac floor for another day after that, and finally released after a 10-day hospital stay. I have never had any cardiac issues before, and all of this was completely out of the blue. My blood pressure also spiked during that time period, and the hypertensive emergency (220/140 blood pressure readings in the ER) that was a factor in me being admitted to the hospital continues to not be completely resolved, as I am on 3 blood pressure medications now (all introduced during that hospitalization) but still experience high blood pressure some days. I was released from the hospital the first time on December 9, but I  am continuing on a treatment of colchicine and a taper of prednisone (started at 60 mg/day and currently at 40 mg/day) for the pericarditis and pericardial effusion, and for the myocarditis I have been giving lifting restrictions (no more than 10 pounds, to last for six months) and restrictions on how high I can allow my heart rate to rise when I do gentle exercise (no higher than 80-90 bpm). The level of fluid in the pericardium is still not back to normal, and I am told that my recovery will take until at least summer (approximately June).  I was re-admitted to the cardiac floor (non-ICU) briefly on December 14-15, because of worsening symptoms, so that accounts for my 11th day in the hospital.   I do have any autoimmune disorder, Mixed Connective Tissue Disease, and I am unsure if that played a role in this myopericarditis with pericardial effusion--it was a major question for the cardiology team while I was in the ICU, who also brought in a rheumatology team to consult and run additional tests, but the rheumatology team was never able to prove that the situation was caused by autoimmune involvement (for example, it did not appear to be a lupus-style attack on the heart tissue because the complements in the immune system did not activate). However, my rheumatologist told me that while I was in the hospital with myopericarditis that she had 3 additional patients who developed sudden heart issues similar to mine shortly after receiving their Moderna boosters.   Again, I understand that correlation is not causation, and it could be that the vaccine was not the cause of my situation. However, if the data you gather from VAERS reports and other sources points to an increased risk of heart problems for patients dealing with autoimmune diseases, please warn those who should avoid this particular vaccine. I support vaccination, and I want people to be vaccinated against COVID-19 (myself included, though my rheumatologist has told me not to get the Moderna vaccine again), but I don't want others to have to go through what I went through--feeling so sick and scared, being separated from my daughter for 10 days, huge medical bills, etc.