A study published online (scheduled for regular publication in July 2021) recommends that women wait about a month after receiving a COVID-19 vaccine to get a routine mammogram. The study notes that a side effect of the vaccine may mimic a common symptom of breast cancer, leading to unnecessary further evaluation.
According to the CDC, about 11% of people receiving the first dose of the currently available vaccines experience swelling in the lymph nodes, and about 16% of people experience this reaction after the second dose of the vaccine. This is a normal reaction and indicates that the body is mounting an immune response to the coronavirus that causes COVID-19.
However, according to Dr. Brett Parkinson – medical director of Intermountain Healthcare’s Breast Care Center – when swollen lymph nodes in the armpit show up in a mammogram, it is usually a cause for concern and often results in further evaluation for breast cancer, lymphoma, or leukemia. To avoid this false positive mammogram result causing needless further examination and accompanying mental stress, women should delay any routine mammogram for 4-6 weeks after their final dose of the vaccine. (That means the second dose for the vaccines that are currently available; when the Johnson & Johnson one-dose vaccine becomes available, that means after the one and only dose.)
However, Parkinson emphasizes that if a woman is experiencing signs of breast cancer (such as bloody discharge from the nipple or a lump in the breast) she should not delay a mammogram. He also reiterates that women should not completely skip their yearly screening: “Postponing it by a month or two will not be that impactful. Postponing it by a year really could be.”