Don’t Delay Mammograms after Vaccination

After a vaccination, including COVID-19 vaccinations, lymph nodes can swell. This is a harmless sign that the vaccine is working. But swollen lymph nodes can show up on a mammogram. Should you delay your mammogram after you’ve had a vaccination? A new study says don’t delay mammograms after immunization and the physicians at The Breast Center agree. 


Swollen lymph nodes, or lymphadenopathy, can be a common sign of infection or inflammation. Lymph nodes are small organs that are part of your immune system. They can be found throughout the body, but can most often be noticed in the neck and under the arms.

A mammogram covers the tissue of the breast, including the area under the arms, called the axilla. Swollen lymph nodes in this area may show up on a mammogram.

Swollen lymph nodes in the axilla often can be a sign of infection, inflammation, breast cancer, and other health issues. However, when they swell as a reaction to a vaccination, they do not signal any worrisome health issues.

Don’t delay mammograms

For one thing, swollen lymph nodes after a COVID vaccine can show up for as long as 43 weeks, according to the researchers.  While they were most visible for about two weeks after the vaccination, they persisted long enough in some patients that delaying mammograms would not have prevented them from showing up on imaging.

The study followed more than 1,200 vaccinated patients for six months. 44% of the women had swollen axillary lymph nodes — far more than typically seen before the pandemic. 

The researchers concluded that there is no reason to delay mammograms after vaccinations and we strongly agree because early breast cancer detection is key. When you have your mammogram you should inform your mammography technologist if you have had a vaccination and in which arm it was placed. This will help your physician provide you with the most accurate results. 

Mammograms are recommended on an annual basis beginning at age 40 for women of average risk. Contact The Breast Center to schedule a screening mammogram.