Should I Wait to Get a Mammogram Following a COVID-19 Vaccine?

Amid the COVID-19 vaccine rollout, there’s been a surprising vaccine side effect that’s been drawing a lot of attention. It seems that swollen lymph nodes in the armpit and collarbone area are a fairly prominent side effect of both the Pfizer-BioNTech and Moderna vaccines. These swollen lymph nodes are temporary and not a cause for concern, researchers say. But in some cases, they could be mistaken as a sign of breast cancer in mammogram results.

The reason some people experience swelling after vaccination is because our lymph nodes play an important role in the immune system. We have lymph nodes throughout our bodies, but there are clusters of them in the neck, armpits, chest, and a few other areas. They help us fight infection and disease, and may swell as a result of the immune system’s healthy response to the vaccine. This swelling is normal and nothing to worry about. The confusion comes in because breast cancer can also cause swelling in the lymph nodes and look similar on a mammogram.

This leaves many people wondering if they should delay their mammogram to avoid potentially unclear, confusing, or alarming mammogram findings. At the same time, mammograms play a crucial role in detecting breast cancer, so they shouldn’t be avoided altogether.

The Mayo Clinic recommends continuing with mammograms as scheduled, even following a COVID-19 vaccination. But they stress the importance of notifying your healthcare provider about your vaccination, including the vaccine date and the arm in which the vaccine was administered. This information can help your healthcare provider better understand the mammogram results, especially if they detect swelling in your lymph nodes on the side of the body that you were vaccinated.

Another option supported by healthcare providers is to postpone your screening mammogram to four to six weeks after your final vaccine dose, giving time for any swelling to subside.

“Having a screening mammogram soon after vaccination may cause unnecessary worry about swollen lymph nodes,” says Monte Swarup, MD, an ob/gyn at Arizona OBGYN Affiliates. “Waiting four to six weeks after your final vaccine dose before having a screening mammogram will diminish the concern for a false positive result and its associated anxiety. Please do not delay any diagnostic mammograms.”

If you’re still feeling unsure about when to have your mammogram, check with your healthcare provider for their recommendation.

If you would like to meet with a knowledgeable doctor, consider contacting Arizona OB/GYN Affiliates (AOA) at 602-343-6174 or visit We have offices in Phoenix, Ahwatukee, Casa Grande, Goodyear, Scottsdale, Gilbert, and Chandler.