Does the updated COVID shot affect mammogram results?

A sore arm, fatigue, fever and chills are all known as possible side effects of the updated COVID-19 vaccine. However, some fear that a lesser-known side effect could result in a false positive finding on a mammogram.

“Some patients who have been recently vaccinated may experience axillary adenopathy, also known as swollen lymph nodes, in the armpit,” says Dr. Patricia Poole, a radiologist affiliated with Sharp Coronado Hospital. “Previously, there was concern this could be confused as a possible sign of breast cancer for those who have a mammogram after being vaccinated.”

Both the Society of Breast Imaging (SBI) and the Centers for Disease Control and Prevention (CDC) have reported that swelling or tenderness in the armpit was a recognized side effect of COVID-19 vaccines. The inflammation is a normal response of the immune system to the vaccine and suggests that antibodies are at work protecting against the virus that causes COVID-19.

A change in screening recommendations

According to Dr. Poole, early in the pandemic, it was advised that having a mammogram soon after vaccination may cause unnecessary worry about swollen lymph nodes. But the guidelines have been revised, and the SBI no longer recommends that women delay screening mammograms after COVID-19 vaccinations.

However, it is important that individuals scheduling mammograms provide information on their COVID-19 vaccination status, including the date and side — left or right — of vaccination. And care providers should let patients know that results indicating swollen lymph nodes are to be expected and not normally of concern.

If lymph node swelling is detected during a mammogram, and it is assumed to be due to vaccination, your care provider may recommend a follow-up mammogram 12 or more weeks later. If lymph node swelling is still present on the follow-up exam but has not changed, a six-month follow-up mammogram may be recommended. If the lymph nodes are getting larger, a lymph node biopsy may be ordered to exclude the presence of cancer.

“Along with getting vaccinated for COVID-19, it’s important to come in for your mammography screening when it is recommended,” says Dr. Poole. “Regular screening mammograms lead to early detection of breast cancer.”

And, as always, Dr. Poole advises diagnostic mammograms should never be postponed if you are experiencing symptoms of breast cancer. “If you find a new lump or concern, you should not delay your health care,” she says.

Learn more about mammography services at Sharp HealthCare.