Dr. Howard Smith Oncall

  Vidcast:  https://youtu.be/MXWJrM0Zwwo   The risk of severe adverse events after the THIRD dose of either Moderna or Pfizer mRNA vaccines is comparable to those following the SECOND dose, and that risk is low in the 0.2 to 0.4% range.  Investigators at the Mayo Clinic and the Cambridge, MA Nference company studied 9,095 persons who received 3 doses of Moderna vaccine and 38,094 persons who received 3 doses of Pfizer vaccine comparing their reactions after their third shot to those after their second one.   These charts show that the most common adverse events were only somewhat more common after the 3rd compared with the 2nd shot.  The exception was in the incidence of swollen glands, usually in the arm pit nodes that drain the vaccination site in the upper arm.  In general, adverse events were more common after the 3rd shot of Moderna vaccine compared with the Pfizer.   Side effects triggering an emergency department visit were greater for the 3rd than the 2nd shot but not significantly greater.  ER visits