Swollen lymph nodes under the armpits after the COVID-19 vaccine may mimic the symptoms of breast cancer – what you need to know

A leading breast imaging organization in the country is recommending that women wait to schedule a mammogram until four weeks after the COVID-19 vaccine due to concerns about a new strange side effect.

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The Society of Breast Imaging (SBI) is warning that women who have recently been vaccinated may have swelling and a lump in the lymph nodes in their armpits, which can be mistaken for a sign of breast cancer. The SBI issued the recommendation in a recently released three-page document that warns of the risk of the vaccine causing axillary adenopathy, also known as a change in the size and consistency of the lymph nodes in the armpit that could be a sign of breast cancer. (In the case of breast cancer, axillary adenopathy can be a sign that the breast cancer has spread.)

Although the SBI says axillary adenopathy is “rare” in general and “rarely reported” after HPV and flu vaccines, it also notes that women who have recently been vaccinated against COVID-19 may have it.

The SBI cites data that found 11.6% of patients who received the vaccine Moderna COVID-19 had swelling or tenderness after receiving their second injection and that lymphadenopathy, ie swelling, occurred in more than 1% of people in clinical trials . These symptoms were more rare in people who received the Pfizer-BioNTech COVID-19 vaccine, but they did occur.

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It is worth noting: the SBI guidance also says that the “real incidence rate” of these symptoms is “probably higher” with both vaccines – meaning that more women are likely to have experienced this side effect and have not noticed or reported it .

As a result, the SBI issued this recommendation: “If possible, and when this does not unduly delay care, consider scheduling screening tests before the first dose of a COVID-19 vaccination or 4-6 weeks after the second dose of a COVID Vaccination -19. “The SBI also recommends that doctors find out the patient’s vaccination status before their mammogram and when the vaccine was given.

The main concern: a vaccinated woman may fear that she developed breast cancer after detecting a lump in the breast or receiving a false reading on her mammogram and being subjected to unnecessary tests.

Although the news is a little strange, doctors are not shocked by what is happening. Here’s why.

First, a recap of how your lymphatic system works

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

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

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

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Here are the ‘official’ side effects of the COVID-19 vaccine

The CDC lists the following potential side effects of receiving the Moderna or Pfizer COVID-19 vaccine:

• Pain in the arm where you received the injection
• Swelling in the arm where you received the injection
• Fever
• Chills
• Tiredness
• Headache

OK, so why can the COVID-19 vaccine mimic the symptoms of breast cancer?

It’s all part of your immune system’s reaction to the vaccine, says William Schaffner, MD, an infectious disease specialist and professor at Vanderbilt University School of Medicine Health. “The lymph nodes are part of your immune system and, although you are inoculated on the outside of the arm, some of this material can enter the local lymph nodes,” he explains. “They can be activated as part of the immune system’s response.” Indicate sensitivity and swelling.

This can happen with certain vaccines and infections, said infectious disease specialist Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Safety. Health. “Any type of immune stimulation will end up affecting the lymph nodes near the site of the infection or injection,” he says.

Discomfort – and potential outbreak – aside, Dr. Schaffner says the swelling is not necessarily a bad thing: “It is further proof that your immune system is being awakened and is responding to the vaccine.”

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How long will this symptom last and what should you do if you experience this after being vaccinated?

It is not entirely clear, but Dr. Adalja says that the swelling and tenderness of the lymph nodes may persist for a while. “It usually lasts about a week,” he says, adding that it may take longer. That’s why Dr. Schaffner says the recommendation to wait four weeks after the vaccine to get a mammogram is “good advice”.

Although a lump or swelling near the breast may be related to the COVID-19 vaccine, it can also be a sign of another infection or even breast cancer. Dr. Schaffner recommends calling your doctor if you notice this symptom and it does not go away in a week or if you feel that the discomfort is getting worse. And, says Dr. Adalja, if you had the swelling before you were vaccinated, be sure to get tested.

But, if you have a lump or swelling, the pain is manageable and you are almost sure it is due to the COVID-19 vaccine. Dr. Adalja says you can try applying cold compresses to the area to try to get relief.

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

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