"I initially had to sit down for about 15 minutes and felt my mouth dry, my tongue was kind of tingling, not swollen. I was checked for anaphylactic shock. I felt like an adrenaline shock and felt my heart racing, my blood pressure was high–stayed in the emergency room for an hour for observation," he wrote. "I felt the same kind of sensation when I had COVID in July."

He was just one of over a thousand people injected with the COVID-19 vaccine, who experienced adverse effects of the medicine. Some 308 of them ended up in an emergency room.

A woman from Michigan vaccinated on Dec. 16, 2020 was sent to an emergency room after experiencing dizziness, lightheadedness, chest tightness and hand tingling. She thought she had a panic attack. A health worker at Bartlett Regional Hospital in Alaska was taken to the emergency room and spent several nights there with a suspected severe allergic reaction, or anaphylaxis, after receiving Pfizer's vaccine.

Some patients reported that they experienced nausea, tremors, stabbing pain and wheezing. Reports from the patients sent to hospital emergency rooms were documented on the Vaccine Adverse Event Reporting System (VAERS). (Related: New study claims vaccinated children appear to be "significantly less healthy" than unvaccinated.)