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COVID-19 Vaccines May Cause False Positives on Mammograms

March 05, 2021
doctor holding mammography250

Since the first of the COVID-19 vaccines began to roll out in late December, radiologists across the country have seen an increase in abnormal mammograms showing swollen lymph nodes.

A stressful phone call

“The presence of swollen lymph nodes, although rare, on a mammogram could be a sign of breast cancer requiring an additional exam or even a biopsy. When women receive a callback after a mammogram, it can be quite anxiety producing, but usually doesn’t mean cancer,” said radiologist Dr. Jennifer Hadro, medical co-director of Breast Imaging at Baystate Health.

To save women the anxiety over a possible false positive, the Society of Breast Imaging released the following statement:

“If possible, and when it does not unduly delay care, consider scheduling screening exams prior to the first dose of a COVID-19 vaccination or 4-6 weeks following the second dose of a COVID-19 vaccination.”

A sign the vaccine is working

“Swollen lymph nodes on the side of the injection are not unusual after being vaccinated against other viruses such as the flu and may actually be a good sign. Their presence is an indication that the vaccine is likely doing its job and your body is beginning to build up an immunity to the virus,” Dr. Hadro added.

Women with irregular results on their mammograms will need a follow-up after their second dose of the vaccine in order to be certain that the inflammation was nothing more than a side effect to the vaccine.

“The recommendations above apply to screening mammography only, meaning women without any concerns such as a lump or other breast changes. We know that mammograms save lives, and if your doctor has ordered a mammogram as a precaution after feeling a lump or other concern, it’s important to keep that appointment even if you have been vaccinated in the past 4-6 weeks,” said Dr. Hadro.

Learn more about the COVID-19 vaccines.

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