Top Mammogram and COVID-19 Vaccine Questions

The short answer: Keep your mammogram appointment

During the COVID-19 epidemic, people dealt with many unknowns and confusion about disease and vaccination side effects. For people with breasts, these include concerns about the COVID vaccine, mammogram timing, and worries about breast cancer.

Despite what you may have read or heard, neither COVID-19 nor the vaccine has been shown to cause breast cancer or any other type of cancer.

The vaccine can cause harmless, temporary swelling of lymph nodes under the arm where the shot was received. Swollen lymph nodes show up on mammography and may require callbacks for additional tests.

Guidelines about the timing of mammography after vaccination changed in 2022. This article will explain the current guidelines and provide information about side effects to breasts and lymph nodes that might occur after vaccination.

Person getting a COVID vaccine

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Changes to the Society of Breast Imaging Guidelines

The Society of Breast Imaging (SBI) is a Virginia-based non-profit membership organization. The organization supports the expertise, influence, and development of breast imagers.

SBI's purpose is to eliminate confusion about when and how often to get a mammogram for those seeking breast screening. In February 2022, SBI changed its guidelines about timing for COVID-19 vaccines and mammography.

Beginning of COVID

Vaccination against COVID-19 began in late December 2020. Several months later, the SBI released its first set of guidelines on mammography and vaccination timing.

In the early days of vaccination, breast radiologists started to notice higher-than-normal rates of swollen lymph nodes in armpits (axillary adenopathy or lymphadenopathy) on screening mammograms. It was surmised that COVID-19 vaccines were causing this localized immune response in the arm that received the vaccine.

Studies on this side effect were not yet available. Given the vaccine's newness, it was unknown how common swollen lymph nodes were or how long this side effect would last. Some experts assumed in error that vaccine-induced lymph node swelling would go down quickly, within a few days or weeks.

Axillary adenopathy can be caused by several conditions, including viral or bacterial infections and breast cancer. When swollen lymph nodes show up on a screening mammogram, callbacks and additional testing are often required. This can cause intense stress and emotional discomfort.

To minimize unnecessary testing and distress, the SBI recommended that people have their screening mammogram done before getting their first COVID vaccine. Alternatively, people were told to wait for a mammogram for four weeks or longer after getting their second COVID shot.

During the winter of 2021, it was hard to get vaccination appointments. The SBI urged people to keep their vaccination appointment and reschedule their screening mammogram appointment if both were already calendared.

People were also urged to let their mammography technologist know if and when they had received a COVID-19 vaccine and the arm it was given in.

As time went on and studies were done, it became clear these early guidelines required revision.

Current Recommendations

In early 2022, the SBI revised its guidelines on vaccination and breast cancer screenings. The SBI no longer recommends delaying screening mammograms or sonograms to accommodate COVID-19 vaccination timing.

The new, revised guidelines refer to average-risk people with no history of breast cancer or a previously diagnosed malignancy (cancerous tumor) that might affect lymph nodes in the armpits. This revised guideline considers medical opinion pieces, position statements, and multiple single-institution retrospective studies.

Much of this has to do with timing. Studies have found that axillary lymphadenopathy may persist for as long as 43 weeks after vaccination. Given the ongoing need for COVID booster shots, delaying mammograms and other breast imaging tests to get boosters could have harmful results for people with early or undiagnosed breast cancer.

In addition to changes in timing, the SBI recommends that screening facilities continue to collect information about COVID-19 vaccination status from people undergoing mammograms and other radiological tests. This information should include the date of the vaccine and which arm received the shot.

Vaccine, Swollen Lymph Nodes, and Mammogram Results

Reactive axillary adenopathy after COVID-19 vaccination occurs in 2.4% to 35% of people undergoing screening mammograms or ultrasounds. The swelling is a good thing. Axillary adenopathy after vaccination indicates that your body is making antibodies to fight disease.

However, swollen lymph nodes in an armpit can also be a sign of breast cancer. It may be stressful, but callbacks and follow-up testing might be needed, especially if your screening uncovers additional suspicious findings. Your personal and family history of breast cancer will also be considered.

Before the existence of COVID-19 vaccines, baseline rates of axillary adenopathy were estimated to be low, at 0.02% to 0.04%. Given the spike in occurrence, it’s important that people undergoing screenings are prepared and given information about this potential side effect.

Vaccine Safety in Diagnosed Breast Cancer Patients

The American Cancer Society and the National Comprehensive Cancer Network recommend that all people with cancer get fully vaccinated against COVID-19.

People undergoing treatment for breast cancer can safely get any COVID-19 vaccine they choose. The Centers for Disease Control and Prevention (CDC) prefers the Johnson & Johnson (Janssen) vaccine to be the last choice for people 18 or older who can't get or don't want one of the other vaccines.

The COVID vaccine may be less effective in people undergoing breast cancer treatment than in healthy people without cancer. While needed to fight your disease, treatments such as chemotherapy, radiation, and immunotherapy weaken the immune system.

Therefore, it's essential to take extra precautions (in addition to vaccination) to avoid getting sick. These include social distancing and mask-wearing.

Your healthcare provider may suggest a different vaccine schedule if you have a weakened immune system. Talk to your healthcare provider to determine which vaccine and vaccine schedule they recommend.


In 2022, the Society of Breast Imaging (SBI) changed its recommendations about scheduling breast cancer screenings and COVID-19 vaccinations. COVID-19 vaccines can cause temporary swelling of lymph nodes in the armpit of the arm that receives the shot. This side effect is harmless and does not lead to breast cancer.

Swollen lymph nodes caused by vaccination (reactive axillary adenopathy) can be seen on screening tests. Despite this, the SBI's current guidelines state that no wait time is needed between vaccination and breast cancer screening tests, including mammography and sonography.

It is important, however, to let your breast radiologist know your vaccine history, so they can consider it when reviewing your results.

A Word From Verywell

You're not alone if you've been worrying and wondering about when to schedule your mammogram and COVID-19 vaccine. These are stressful times to navigate the ins and outs of being your healthiest self.

It's important to take the SBI's guidelines to heart. Statistically, fewer people have been getting their regular, annual breast cancer screenings than they did before COVID hit. Make that call today if you know you're due for a mammogram.

Frequently Asked Questions

  • Does the COVID-19 booster affect mammogram results?

    It may. Up to 35% of people have experienced lymph node swelling in their armpits after vaccination, which could be seen on a mammogram. This swelling is temporary and does not lead to breast cancer.

  • Why does the COVID-19 vaccine cause breast swelling?

    Swelling after the COVID-19 vaccination is caused by lymph nodes in the armpit, which become enlarged and inflamed when fighting an infection. After immunization, this same reaction can take place as the vaccine teaches your white blood cells to produce antibodies to COVID-19. This is a good thing. When you are later exposed to COVID-19, these antibodies can reduce your risk of severe illness.

  • When does lymph node swelling go down after the COVID-19 vaccine?

    The swelling you can feel in your armpit should go down within a few weeks. However, swollen lymph nodes may still be seen during an imaging test for as long as 43 weeks (over 10 months).

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Society of Breast Imaging. Revised SBI recommendations for the management of axillary adenopathy in patients with recent COVID-19 vaccination.

  2. Society of Breast Imaging. SBI mission and awards.

  3. Wolfson S, Kim E, Plaunova A, et al. Axillary adenopathy after COVID-19 vaccine: no reason to delay screening mammogram. Radiology. 2022;303(2):297-299. doi:10.1148/radiol.213227

  4. Wolfson S, Kim E. Breast cancer screening and axillary adenopathy in the era of COVID-19 vaccination. Radiology. 2022:222040. doi:10.1148/radiol.222040

  5. American Cancer Society. COVID-19 vaccines in people with cancer.

By Corey Whelan
Corey Whelan is a freelance writer specializing in health and wellness conntent.