BOSTON — The COVID-19 vaccine can cause swelling of the lymph nodes in the armpit, mimicking a symptom of breast cancer and often appearing in screening mammograms, radiologists have found.
The side effect in the small glands that help fight infection is normal and should not be cause for alarm, said Dr. Sona Chikarmane, Division Chief of Breast Imaging at Brigham and Women’s Hospital and Dana Farber Cancer Institute.
“Vaccines, including the COVID-19 vaccine, may cause temporary swelling of the lymph nodes on the same side as your vaccine,” Chikarmane told Boston 25 News by Zoom Friday. “This is a normal and expected finding and should go away in a couple of days or up to a week or so.”
The lymph nodes often react to something newly introduced to the body – from the flu shot to a bug bite – Chikarmane said.
If the swelling does not subside or if a woman is concerned about a change in her armpit or breast, she should call her primary care doctor or any breast imaging site, Chikarmane added.
While the inflammation of the axillary lymph nodes may be alarming for some women who fear it is a cancerous lump, experts can tell the difference, even if further imaging is needed.
“The breast radiologists are aware of this finding and know how to interpret it,” Chikarmane said. “So, if we see any swollen lymph nodes on your mammogram and know that you’ve had a recent COVID vaccine, we’re able to interpret it accordingly.”
For that reason, Chikarmane urged women not to wait for vaccine side effects to subside before scheduling their potentially life-saving mammograms. She also advised women not to reschedule their vaccinations, especially when such appointments are often difficult to book.
“We recommend… to not delay your vaccine and not delay scheduling your screening mammogram,” Chikarmane said. “Both are incredibly important steps to take in protecting women’s health.”
Chikarmane encouraged women getting mammograms to let the radiologists know if they have recently received their vaccine, which arm the shot was in and if it was a first or second dose.
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