COVID Vaccine Side Effect or Breast Cancer? Experts Clarify

COVID vaccines can lead to swelling in certain lymph nodes, mimicking breast cancer lump.

3 min read
New side effect from COVID-19 vaccine might be mistaken as breast cancer.  

If you’ve noticed a lump near your armpit and have taken a covid vaccine recently, don’t panic or rush to book a mammography, say experts. It could just be a temporary side effect of the covid vaccine.

The Society of Breast Imaging (SBI), USA, has warned that women who have received the covid vaccine may develop a swelling in the lymph nodes of their armpit, which could be mistaken as a sign of breast cancer, reports Health.

In the statement, the SBI warns that the vaccine can cause axillary adenopathy, i.e. a change in the size and consistency of lymph nodes in the armpit.

According to the Centre For Disease Control, USA, these are the common side effects one can expect after receiving the covid vaccine.

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

Axillary adenopathy is usually seen as a sign of breast cancer having spread.

Although it is rarely reported as a side effect of other vaccinations, the statement also says, “higher rates of axillary adenopathy have been reported with administration of both COVID-19 vaccines currently authorized for emergency use by the US FDA: Moderna and Pfizer-BioNTech.”

“For patients receiving the Moderna COVID-19 vaccine, axillary swelling or tenderness (i.e. lymphadenopathy) was reported in 11.6% of patients following dose 1 and 16.0% of patients following dose 2.”
Society of Breast Imaging, USA

This side effect was found to be rarer in the case of the Pfizer-BioNTech vaccines.

In both cases, Lymphadenopathy occurred in the arm and neck within 2-4 days of vaccination and lasted for about 10 days.

These swollen lymph nodes can show up in a mammogram even if women can’t feel them, and the false positive could trigger undue fear in them.

For this reason, the Society of Breast Imaging recommends that women postpone any mammography scheduled within four weeks after their final COVID-19 shot.

According to WebMD, Swelling and tenderness of lymph nodes after vaccination isn’t just restricted to women but can occur in men too.

What Are Lymph Nodes, and What Causes Them to Swell?

Lymph nodes are your immune system’s first line of defence.

Lymph nodes—little bean shaped glands spread all over the body—help us fight illness and infections by recognising and killing germs.

When trying to filter out bad cells, lymph nodes around an injury or infection may swell up. And, while lymph node swelling is usually a sign of an infection, it can also be a sign of cancer.

Because lymph nodes kick into action when they come across foreign cells that they perceive as ‘bad’, they can sometimes swell up in response to certain vaccines.

Other Signs of Breast Cancer That You Should Watch Out For

Women who find a swollen lymph node in the armpit should not automatically suspect breast cancer, but there are other telling signs of breast cancer that you mustn’t ignore. According to the CDC these are,

  • Thickening or swelling of part of the breast.
  • Irritation or dimpling of breast skin.
  • Redness or flaky skin in the nipple area or the breast.
  • Pulling in of the nipple or pain in the nipple area.
  • Nipple discharge other than breast milk, including blood.
  • Any change in size or shape of the breast.
  • Pain in any area of the breast.

(Written with inputs from WebMD and Health)

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