Patients who receive the Pfizer-BioNTech or Moderna COVID-19 vaccine can experience swollen lymph nodes in the armpit on the side where the shot was administered, but physicians say there is no need to panic.

Inflammation of the lymph nodes is common after getting a vaccine that prompts a strong immune response - including the current COVID-19 vaccines, said Georgia Spear, MD, Chief of the Department of Breast Imaging at NorthShore. Although the reaction is harmless, it may feel like a lump, causing undue fear for women.

Up to 11.6 percent of vaccine recipients may experience this side effect after one dose, and 16 percent after the second dose, according to the Centers for Disease Control and Prevention. The enlarged lymph nodes typically appeared within 2-to-4 days post-vaccination.

Swollen lymph nodes can show up on a mammogram even if women can’t feel them. Given the likelihood this side effect will develop in a significant number of patients as the vaccine rollout continues, NorthShore is following mammogram guidelines set forth by the Society of Breast Imaging:

• If you are symptomatic (suspicious lump, etc.) DO NOT delay care or cancel your mammogram, talk to your doctor
• If asymptomatic (no suspicious lumps) don’t delay your vaccination, simply schedule your mammogram four weeks after you receive your second dose of the vaccine
• If you are a NorthShore patient, a vaccine questionnaire will appear when scheduling your mammogram on NorthShoreConnect and will provide you with the appropriate appointment options

Remember that women age 40 and older should get mammograms every year, according to the American Cancer Society.

To schedule a mammogram call 888-364-6400 or schedule online here.