What You Should Know About the COVID-19 Vaccine and Mammograms

Lymph Nodes as a Line of Defense

Found throughout the body, lymph nodes contain white blood cells to fight off infection and disease and filter foreign particles. When activated, they trigger the body’s adaptive immunity to fight off unwanted antigens.

The underarm contains roughly 20 to 40 lymph nodes. When the body’s immune system detects the presence of foreign invaders (like the COVID-19 vaccine), it triggers the production of white blood cells. The white blood cells in the lymph nodes increase and begin filtering foreign particles, causing them to swell.

COVID-19 Vaccines May Cause Swelling in the Lymph Nodes

Some people who receive a COVID-19 vaccine may experience swollen lymph nodes on the same side of the body where they received the injection. Swollen lymph nodes are a normal reaction to the COVID-19 vaccine.  In a few days, these swollen lymph nodes will usually return to normal on their own.

How Swollen Lymph Nodes Can Impact Your Mammogram Results

Radiologists look closely for any changes on your mammogram. Swollen lymph nodes under one arm can be seen on a mammogram and can impact your mammogram results. Be sure to notify the technologist giving your mammogram if you’ve received the COVID-19 vaccine.

When to Schedule Your Mammogram

It is best to try to schedule your screening mammogram before your first dose of the COVID-19 vaccine.

After you’ve been vaccinated, schedule your mammogram at least 4 weeks after your second dose of the COVID-19 vaccine. Your body’s immune response to the vaccine can cause temporary swelling of lymph nodes. The swelling will need to subside to avoid impacting your mammogram results. If you need a mammogram, talk to your OBGYN to see if it is appropriate to delay your exam.