Anaphylaxis, an acute and potentially life-threatening allergic reaction, has been reported rarely following COVID-19 vaccination. These interim considerations provide recommendations on assessment and management of anaphylaxis following COVID-19 vaccination. Detailed information on CDC recommendations for vaccination, including contraindications and precautions to vaccination, can be found in the Clinical Considerations for Use of COVID-19 Vaccines Currently Authorized in the United States. Patients should be screened prior to receipt of each vaccine dose, and those with a contraindication should not be vaccinated. A COVID-19 prevaccination questionnaire pdf icon[6 pages] is available to assist with screening.
Personnel, medications, and supplies for assessing and managing anaphylaxis
Healthcare personnel who are trained and qualified to recognize the signs and symptoms of anaphylaxis as well as administer intramuscular epinephrine should be available at the vaccination location at all times. Vaccination locations that anticipate vaccinating large numbers of people (e.g., mass vaccination clinics) should plan adequate staffing and supplies (including epinephrine) for the assessment and management of anaphylaxis.
The following emergency equipment should be immediately available for the assessment and management of anaphylaxis.
*COVID-19 vaccination locations should have at least 3 doses of epinephrine available at all times, and the ability to quickly obtain additional doses to replace supplies after epinephrine is administered to a patient. People with a history of anaphylaxis who carry an epinephrine autoinjector could be reminded to bring it to their vaccination appointment. Detailed information on storage, handling, administration, and dosage considerations is available in the package inserts for epinephrine (e.g., EpiPen®). Expired epinephrine or epinephrine that appears to be in unacceptable condition (per the manufacturer’s package inserts) should be replaced.
†Antihistamines may be given as adjunctive treatment but should not be used as initial or sole treatment for anaphylaxis. Additionally, caution should be used if oral medications are administered to people with impending airway obstruction.
‡Either an automated or a manual blood pressure monitor, with appropriate cuff sizes, is acceptable. If a manual blood pressure monitor is used, a stethoscope should also be available.
Routine observation periods following COVID-19 vaccination*
CDC currently recommends the following observation periods after vaccination:
30 minutes for:
People with a history of an immediate allergic reaction of any severity to another vaccine or injectable therapy.
People with a contraindication to a different type of COVID-19 vaccine (for example, people with a contraindication to mRNA COVID-19 vaccines who receive Janssen viral vector vaccine should be observed for 30 minutes following Janssen vaccination).
People with a history of anaphylaxis due to any cause.
15 minutes for: All other persons
* Note: People may be observed for longer, based on clinical concern. For example, if a person develops itching and swelling confined to the injection site during their post-vaccination observation period, this period may be extended to assess for development of any hypersensitivity signs or symptoms consistent with anaphylaxis (described below).
Early recognition of anaphylaxis
Because anaphylaxis requires immediate treatment, diagnosis is primarily made based on recognition of clinical signs and symptoms, including:
Respiratory: sensation of throat closing or tightness, stridor (high-pitched sound while breathing), hoarseness, respiratory distress (such as shortness of breath or wheezing), coughing, trouble swallowing/drooling, nasal congestion, rhinorrhea, sneezing
Gastrointestinal: nausea, vomiting, diarrhea, abdominal pain, or cramps
Cardiovascular: dizziness; fainting; tachycardia (abnormally fast heart rate); hypotension (abnormally low blood pressure); pulse difficult to find or “weak”; cyanosis (bluish discoloration); pallor; flushing
Skin/mucosal: generalized hives; widespread redness; itching; conjunctivitis; or swelling of eyes, lips, tongue, mouth, face, or extremities
Neurologic: agitation; convulsions; acute change in mental status; sense of impending doom (a feeling that something bad is about to happen)
Other: sudden increase in secretions (from eyes, nose, or mouth); urinary incontinence
Anaphylaxis should be considered when signs or symptoms are generalized (i.e., if there are generalized hives or more than one body system is involved) or are serious or life-threatening in nature, even if they involve a single body system (e.g., hypotension, respiratory distress, or significant swelling of the tongue or lips).
Symptoms of anaphylaxis often occur within 15-30 minutes of vaccination, though it can sometimes take several hours for symptoms to appear. Early signs of anaphylaxis can resemble a mild allergic reaction, and it is often difficult to predict whether initial, mild symptoms will progress to become an anaphylactic reaction. In addition, symptoms of anaphylaxis might be more difficult to recognize in people with communication difficulties, such as long-term care facility residents with cognitive impairment, those with neurologic disease, or those taking medications that can cause sedation. Not all symptoms listed above are necessarily present during anaphylaxis, and not all patients have skin reactions.
If anaphylaxis is suspected, administer epinephrine as soon as possible, contact emergency medical services, and transfer patients to a higher level of medical care. In addition, instruct patients to seek immediate medical care if they develop signs or symptoms of an allergic reaction after their observation period ends and they have left the vaccination location.