What you should know about COVID-19 Vaccines and Your Mammogram


We know how important mammogram screenings are in the early detection of breast cancer and that COVID shut-downs and quarantines caused many women to miss this important exam last year, putting themselves at risk for detection of cancers at later stages.  

We also know that there is a sense of urgency to get as much of the population vaccinated as possible against COVID-19 so that we can achieve some sort of herd immunity and life can go back a little closer to normal. 

However, what we are now learning is how the timing of your vaccine and mammogram may affect what the radiologist sees and interprets on your mammographic image. 

New guidelines for when to time your mammogram after your vaccine

The Society of Breast Imaging (SBI) is advising women who have recently received the COVID-19 vaccine that they should wait 4-6 weeks after their second vaccinations before having their mammogram.

The reason for this is that the body’s immune response to the vaccine can cause swelling and/or a lump in their armpit on the side where they received the vaccine. 

Although swollen lymph nodes are a fairly normal reaction to a vaccine, this swelling shows up on the mammographic images and can be interpreted as cancer

What are swollen lymph nodes and how do they relate to breast cancer?

The body’s lymph nodes are a part of the immune system and are responsible for removing potentially harmful substances i.e. unwanted cells from an infection, from the body. As the lymph nodes work harder to remove waste, they enlarge. This typically occurs in the neck, armpit, and groin. 

It’s not uncommon to have swollen lymph nodes when you have the flu, a viral infection like the chickenpox, or even Lyme disease
Rarely, swollen lymph nodes can be a sign of breast cancer.

When the lymph nodes first swell, one might feel pain or tenderness in the area. The swelling can last anywhere from a few days to up to two weeks

Usually if the radiologist sees a swollen lymph node on the mammogram, they will have the patient come back to do an additional screening depending on the patient’s medical history. 

How the COVID-19 vaccine can affect your mammogram

underarm_pain_hidpiSBI cited data that found 11.6 % of patients who took the Moderna vaccine reported swelling or tenderness under their arm after the first dose and 16% of patients after the second dose. These symptoms were rarer when given the Pfizer vaccine. 

It is also worth mentioning, that SBI’s new guidance suggests that the true incident rate is “likely higher” with both vaccines. Which means that women experienced the swelling but did not report it. 

Since the swelling can last a few days SBI suggests that when scheduling a mammogram, have it performed before the first dose of either vaccine or at least 4 weeks after the second dose. This will reduce the likelihood of swollen lymph nodes presenting in the mammogram.

If the vaccine is scheduled close to an already scheduled mammogram, it is suggested that the vaccination appointment is kept and if possible, reschedule the mammography appointment. 

However, if the mammogram is already overdue or cannot be rescheduled, both appointments should be kept. Both are important for a patient’s overall health and to stop the spread of COVID-19.

Patients should notify their mammographer prior to the screening if they suspect a swollen lymph node under their arm, keeping in mind the date they received the vaccine and if it was the first or second dose. 

The importance of both mammograms and the COVID-19 vaccine

vaccine_hidpiWomen over the age of 40 are encouraged to start getting mammogram screenings once a year. Mammogram screenings are the best way to catch cancer and are proven to catch breast cancer earlier than any other precautionary measure. This leads to more successful treatments if cancer is detected.  

According to the CDC, the COVID-19 vaccines that are available in the United States have shown to be highly effective at preventing the spread of COVID-19. 

They also believe that the vaccines may help you from getting critically ill if you do, in fact, get COVID-19. Receiving the vaccine while adhering to social distancing and mask wearing guidelines is the best way to protect yourself from getting and/or spreading this deadly disease. 

Although the COVID-19 vaccines can potentially delay a mammogram screening, both are still extremely important in keeping up with your overall health.  

Megan Sargalski

Megan Sargalski

Marketing Communications Specialist

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