Shortly after COVID-19 vaccines became available nationally, a trend began to emerge from mammogram screenings.
“When patients have a COVID-19 vaccination, one of the side effects is it can cause lymph nodes in your underarm region to become swollen or enlarged, which is a natural reaction to your immune system responding to the vaccine,” said Dr. Susan Crook, a radiologist who specializes in breast imaging at IU Health North in Carmel. “Sometimes we can see those lymph nodes on the mammogram, and in the absence of a vaccine history, swollen lymph nodes on a mammogram can be a symptom of something that is wrong.”
Normal swelling from the vaccine can provide an abnormal reading of the mammogram. Typically, the swelling would require additional imagining.
“We were seeing it a lot more in otherwise healthy patients with a vaccine history,” Crook said. “As health care workers first started getting the vaccine and those women came in for mammograms, we found more and more women with enlarged lymph nodes.”
Crook, however, said it doesn’t happen with all patients who get the vaccine.
Crook said the Society of Breast Imaging created guidelines IU Health is following, such as recommending patients schedule their mammogram screening prior to having their vaccine or four weeks after their second dose of the vaccine.
“The lymph nodes go back to normal a few days or several weeks after the vaccine,” she said. “So that’s why waiting four weeks is usually adequate time to let those lymph nodes go back to normal. If a patient is having a problem in their breast, like feeling a lump or bloody nipple discharge, they should seek medical attention right away for that. They shouldn’t put it off because of the vaccine.”
Crook encourages patients not to delay getting a COVID-19 vaccine because of a planned mammogram.
“If you have both scheduled, get the vaccine as soon as you can, because that’s the most important thing you can do to help prevent the spread of COVID-19,” Crook said. “The mammogram can be rescheduled.”