COVID-19 mRNA (Moderna) vaccine Disease Interactions

Immunocompromised individuals, including those receiving immunosuppressive therapy, may have a diminished immune response to the messenger RNA COVID-19 vaccine. The US CDC has published considerations related to COVID-19 vaccination for individuals who are moderately to severely immunocompromised (https://www.cdc.gov/covid/hcp/vaccine-considerations/).

Syncope may occur in association with administration of injectable vaccines, including the messenger RNA COVID-19 vaccine. Procedures should be in place to avoid injury from fainting, especially for patients who have previously fainted in association with an injection.

In patients with thrombocytopenia or coagulation disorders, IM injections may produce bleeding and hematomas. Patients with a platelet count less than 50,000/mm3 are at an increased risk. Caution is advised if the vaccine (e.g., plague vaccine; hepatitis A and B vaccines; aluminum-adsorbed DTaP, DTP, DT, or Td) must be administered IM. The risk of bleeding may be minimized by vaccination immediately after the administration of replacement factor, use of a 23-gauge (or smaller) needle, and immediate application of direct pressure to the vaccination site for at least 2 minutes.