Don't Delay Your Mammogram After Getting the COVID-19 Vaccine

Revised recommendations state there is no need to reschedule your next mammogram if it falls close to your vaccination appointment.

The Society for Breast Imaging (SBI) states that patients who were recently vaccinated or received a booster for COVID-19 can experience axillary adenopathy, or swelling in the lymph nodes of their armpit.

While this is a relatively common side effect of getting the COVID-19 vaccine, for women, this can cause anxiety if they see or feel a lump around the breast. SBI shares that healthcare providers can alleviate fears by telling women: "Vaccines of all types can result in temporary swelling of the lymph nodes, which is a sign that the body is making antibodies in response to the vaccine, as intended."

Does that mean you need to delay your mammogram? Does having swollen lymph nodes skew the results of your test?

The short answer is no.

In February 2022, Radiology published the results of the largest study evaluating swollen lymph nodes after COVID-19 vaccination among patients receiving mammograms. The study showed that the side effect appeared in 44% of the patients. And this side effect did not impact mammography outcomes.

And SBI agreed, reversing previous recommendations that women wait four to six weeks after vaccination before getting a mammogram, especially since the side effect can persist for quite a while and has been seen up to 43 weeks after COVID-19 vaccination.

Doctors are not concerned about this happening after getting the COVID-19 vaccine or booster. Here's why.

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First, a Recap on How Your Lymph System Works

Your body has a network of lymph vessels and lymph nodes that's part of your immune system. The lymph system collects fluid, waste material, and other things like viruses and bacteria that are in your tissues outside of your bloodstream, explains the American Cancer Society (ACS).

The lymph vessels are similar to your blood vessels, but carry a clear, watery fluid called lymph instead of blood. Lymph fluid can do a few different things, but one important function is its ability to fight infections through the use of white blood cells that it carries. Your lymph nodes are small structures that work as filters for harmful substances, and they contain immune cells that help you fight infections, says the ACS.

When you have an infection, injury, or cancer, the node in that area may swell or enlarge as it tries to filter out the bad cells. And, while lymph node swelling is usually a sign of an infection, it can also signal cancer in that area, says the ACS.

Here Are Some Side Effects of the COVID-19 Vaccine

The Centers for Disease Control and Prevention (CDC) lists the following as potential side effects of receiving the COVID-19 vaccine:

  • Pain and/or swelling in the arm where you received the shot
  • Fever
  • Chills
  • Tiredness
  • Headache

OK, So Why Swollen Lymph Nodes?

"It's all part of your immune system's reaction to the vaccine," William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, told Health. "The lymph nodes are part of your immune system and, although you are inoculated in your outer arm, some of that material can get into your local lymph nodes," explained Dr. Schaffner. "They can be activated as part of the response of the immune system." Cue the tenderness and swelling.

"This can happen with certain vaccines and infections," infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security, told Health. "Any type of immune stimulation will eventually impact the lymph nodes near the site of infection or injection," he said.

Discomfort—and potential freakout—aside, Dr. Schaffner said "The swelling isn't necessarily a bad thing. It's another bit of evidence that your immune system is being awakened and is responding to the vaccine."

And feeling a lump or swelling under the armpit after vaccination should not deter women from getting a mammogram. According to the National Cancer Institute, mammograms have been shown to reduce deaths from breast cancer.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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