"When any foreign substance enters your body, it's the lymph nodes' job to kind of protect the body," Garver said. "And they swell and react in response to any foreign substance.
"When this happens, it's telling us that the lymph nodes are doing their job and they are reacting to something foreign. And in the case of any vaccine, they are mounting an immune response, which is completely normal and what they should be doing. So, it's a normal and healthy response.
"In a tiny percentage of cases, (swollen lymph nodes) could be an indication of cancer in the breast or cancer elsewhere in the body, such as lymphoma."
"Yes. When we see swollen lymph nodes, it could be a sign of cancer," Garver said. "So we'll bring the patient back, and we'll get more history to find out what's going on.
"We'll look for additional findings in the breasts that could be a sign of breast cancer. And if we see anything suspicious, we will biopsy the finding in the breast and or the lymph nodes."
But for women who've gotten COVID-19 vaccines recently, the Society of Breast Imaging recommends doctors wait before performing biopsies.
"They said, 'Hold off on doing those additional biopsies. Get additional imaging, but hold off on biopsying patients because this could be a vaccine reaction,' " Garver said.
"If we do see swollen lymph nodes and you've had a vaccine, we will call you back. We will do an additional ultrasound, and then we'll follow you with ultrasound in three months to make sure that the lymph nodes returned to normal. So the worst case scenario is that we would do an additional ultrasound and then another ultrasound in three months to make sure things resolve."
Q: How long should women wait after getting a vaccine to have a mammogram?
A: "Ideally, at least four weeks," Garver said. "But it's probably better to wait six weeks.