Peer Reviewed

Case in point

COVID Vaccine Arm

Joseph Pagano, DO1 • James Espinosa, MD1 • Alan Lucerna, DO1 • Henny Schuitema, DO1

1Department of Emergency Medicine, Rowan University SOM, Jefferson NJ

Pagano J, Espinosa J, Lucerna A, Schuitema H. COVID vaccine arm. Consultant. Published online March 21, 2023. doi:10.25270/con.2023.03.000003

Received May 30, 2022. Accepted September 1, 2022.

The authors report no relevant financial relationships.

James Espinosa, Department of Emergency Medicine, Rowan University SOM, 18 East Laurel Road, Stratford, NJ 08084 (

Introduction.  A 38-year-old man received a booster dose of the Pfizer COVID-19 vaccine about 6 months after completing two doses of the Moderna COVID-19 vaccine primary series. The patient, who was a physician, chose the Pfizer vaccine for his booster dose because he had experienced chills and headache for about 1 day after receiving the second dose of the Moderna vaccine. The patient had no history of an underlying immune condition.

Case description. At the injection site (left deltoid), he noted shoulder soreness following vaccination. Later that evening, he noted chills and rigors as well as swelling and tenderness around the area of the injection site. He went to bed about 10 hours post-vaccination, but he awoke 2 hours later with rigors and headache that persisted throughout the night. The following day, he had a mild headache but noted some improvement with acetaminophen and ibuprofen. At night, he was again awakened by rigors and increased headache.

On the following the morning (post-vaccination day 2), he noted continued headache accompanied by an overall sense of weakness and subjective fevers. In addition, his left arm showed diffuse axillary edema with no palpable adenopathy. He took 60 mg of prednisone and 25 mg of diphenhydramine with a noticeable improvement in symptoms within 2 hours and near resolution within 12 hours. He slept well, with no rigors.

On post-vaccination day 3, the patient awoke without headache or weakness; he took 60 mg of prednisone and diphenhydramine 25 mg three times per day. He discontinued the medications on post-vaccination day 4. The arm swelling subsided. The patient’s symptoms had entirely resolved by post-vaccination day 5.

Discussion. Approximately 2% of patients who received an mRNA vaccine COVID vaccine report a mild skin reaction at the injection site.1,2 The reaction called COVID vaccine arm, or COVID arm, is characterized by erythema and edema at or near the injection site and may present up to 10 days post-vaccination.2

The mechanism of COVID vaccine arm has not been clearly established. The Moderna and Pfizer vaccines include mRNA and lipids, and both vaccines contain polyethylene glycol and polysobate 80. As Lindgren and colleagues3 report, both compounds have been shown to cause delayed hypersensitivity reactions, however, it is unclear whether these ingredients cause COVID vaccine arm.4,5

Pain at the injection site has been noted with several vaccines, including varicella, diptheria-tetanus-pertussis, influenza, meningococcal, and pneumococcal vaccines.6 The rate of injection-site reactions is about 10% to 20% across these vaccines, and the rate is higher for the meningococcal vaccine at about 50%. Fever is a possible side effect of several vaccines, including varicella, diptheria-tetanus-pertussis, influenza, measles, and meningococcal. The rate of fever with these vaccines is 10% to 20%.6

In a systematic review of the literature, about 24% of patients with COVID vaccine arm experienced arm swelling but also systemic symptoms, such as myalgia, chills, and headache.7 One patient in that review reported lymphadenopathy, which also occurred in our case patient.

COVID vaccine arm may present like a cellulitis. A recent tick bite can be a clue for erythema migrans.3

Patients without significant symptoms may not require any treatment as skin adverse effects are generally self-limited.7 Management of COVID vaccine arm with systemic symptoms can include diphenhydramine and topical corticosteroids.8Importantly, an awareness of COVID vaccine arm may reduce the use of antibiotics for suspected post-vaccination cellulitis.

Our case patient took oral prednisone for 2 days, which appeared to have a salutary effect on his systemic symptoms. A review of the literature did not reveal specific research concerning whether a limited course of prednisone might interfere with vaccine efficacy. Lahood and colleagues9 examined antibody levels after pneumococcal vaccination in adult patients with steroid- and nonsteroid-dependent asthma and found that chronic prednisone treatment did not significantly affect immunoglobulin levels or pneumococcal antibody levels. Similarly, in a group of adult patients with chronic obstructive pulmonary disease, Steentoft and colleagues10 concluded that antibody levels rose after pneumococcal vaccination despite chronic systemic steroid use.Furthermore, a study of children with asthma who received the influenza vaccine showed no decrease in vaccine efficacy at the beginning of burst prednisone treatment.11

Clearly, further research is needed to clarify the relationship of a burst dose of prednisone in patients who have received a COVID-19 vaccine. Until such data are available, the use of a brief course of prednisone in patients with COVID vaccine arm will remain a matter of clinical judgement.

  1. Fernandex-Nieto D, Hammerle J, Fernandex-Escrbano M, et al. Skin manifestations of the BNT162b2 mRNA COVID‐19 vaccine in healthcare workers. ‘COVID‐arm’: a clinical and histological characterization. J Eur Acad Dermatol Venereol. 2021;35(7):e425-e427. doi:10.1111/jdv.17250
  2. Gregoriou S, Kleidona IA, Tsimpidakis A, Nicolaidou E, Stratigos A, Rigopoulos D. 'COVID vaccine arm' may present after both mRNA vaccines vaccination. J Eur Acad Dermatol Venereol. 2021;35(12):e867-e868. doi:10.1111/jdv.17614
  3. Lindgren AL, Austin AH, Welsh KM. COVID arm: delayed hypersensitivity reactions to SARS-CoV-2 vaccines misdiagnosed as cellulitis. J Prim Care Community Health. 2021;12:21501327211024431. doi:10.1177/21501327211024431
  4. Ramos CL, Kelso JM. "COVID Arm": Very delayed large injection site reactions to mRNA COVID-19 vaccines. J Allergy Clin Immunol Pract. 2021;9(6):2480-2481. doi:10.1016/j.jaip.2021.03.055
  5. Saifuddin A, Koesnoe S, Kurniati N, Sirait S, Arisanty R, Yunihastuti E. COVID arm after Moderna booster in healthcare worker: a case report. Acta Med Indones. 2021;53(3):326-330.
  6. Immunization reactions. Seattle Children’s. Revised January 12, 2022. Accessed October 23, 2022.
  7. Fasano G, Bennardo L, Ruffolo S, et al. Erythema migrans-like COVID vaccine arm: a literature review. J Clin Med. 2022;11(3):797. doi:10.3390/jcm11030797
  8. Blumenthal KG, Freeman EE, Saff RR, et al. Delayed large local reactions to mRNA-1273 vaccine against SARS-CoV-2. N Engl J Med. 2021;384(13):1273-1277. doi:10.1056/NEJMc2102131
  9. Lahood N, Emerson SS, Kumar P, Sorensen RU. Antibody levels and response to pneumococcal vaccine in steroid-dependent asthma. Ann Allergy. 1993;70(4):289-294.
  10. Steentoft J, Konradsen HB, Hilskov J, Gislason G, Andersen JR. Response to pneumococcal vaccine in chronic obstructive lung disease--the effect of ongoing, systemic steroid treatment. Vaccine. 2006;24(9):1408-1412. doi:10.1016/j.vaccine.2005.09.020
  11. Fairchok MP, Trementozzi DP, Carter PS, Regnery HL, Carter ER. Effect of prednisone on response to influenza virus vaccine in asthmatic children. Arch Pediatr Adolesc Med. 1998;152(12):1191-1195. doi:10.1001/archpedi.152.12.1191