Covid vaccine messing up breast cancer tests

Lymph nodes enlarged by the vaccine, low fever and sore arms are typical side effects of the inoculation, indicating that the shot is working. But swollen lymph nodes can be interpreted as a false red flag for breast cancer, particularly in a mammogram test. 

Patients with enlarged lymph nodes are typically called back for further testing by technicians. Although doctors do not want to put their patients through unnecessary tension, they err on the side of caution. 

An unheralded piece of human anatomy, the body’s lymphatic system plays a key role in collecting and removing cellular debris from the body. Like rubbish bins set out along well-traveled corridors, the lymph nodes will bulge noticeably if some unusual process is generating more trash than usual.

When the body is fighting an infection — or thinks it is, after a dose of vaccine — the immune system dispatches an army of cells and proteins to mount a defense, leaving a lot of detritus in its wake.

Cancer, too, mobilizes a lot of cellular machinery. It uses the lymphatic system to travel to distant sites and leaves behind a telltale mess.

Close to both the breast and whichever arm gets a jab of vaccine, the 10 to 20 lymph nodes inside each armpit can act as a sentinel when radiologists see signs that they are swollen. But whether a node is enlarged due to infection, vaccine, trauma or cancer is not always clear.