A harmless side effect of the COVID-19 vaccine is leading to false positive mammograms, according to healthcare experts.
About 10 percent of women who received the vaccine in a clinical trial reported swollen lymph nodes under the arm. Because that can also be a sign of breast cancer, Dr. Margarita Zuley, Chief of the Division of Breast Imaging at the University of Pittsburgh Medical Center says the symptom can be scary, but a normal immune response to the vaccine.
"It's not dangerous," she said. "I hope patients won't find it scary. Nothing bad happens from that, and that lymph node will go back down and stop being sore."
Still, Zuley says those harmless swollen lymph nodes are showing up in mammograms, sometimes resulting in false positives.
"We see something on a screening mammogram, we're going to recall those patients to evaluate that finding, but it could actually just be due to the COVID vaccine."
To combat the anxiety of a potential false positive mammogram, Zuley says UPMC is now asking people who come in for a mammogram if they've received the shot and when.
They're also encouraging people to schedule their mammograms before their vaccine or four weeks after their second shot if it does not delay care. People who already have vaccine or mammogram appointments should not reschedule or cancel either.
Zuley says all concerning mammograms will be handled with the same care, even if the person reported getting a COVID-19 vaccine.
"Even if we know that and we see a prominent lymph node, we're still going to ask our patient to return because we want to be very careful," she said. "We don't want to be cavalier and assume that something is due to a vaccination."
The recommended time in between mammograms is eight to nine months.