A woman receives the COVID-19 vaccine during the pandemic in 2021. Credit: WINK News. A coronavirus vaccine side effect is causing concern for women — swollen lymph nodes after the shot. It’s a normal response to an injection that can show up on mammograms as a sign of breast cancer. Health experts we spoke to say there should be no cause for immediate alarm. Rita Bertler knows the value of paying attention to one’s own health. She is the president and founder of nonprofit Dollars for Mammograms. “My mother was a breast cancer victim. She had to have a mastectomy,” Bertler explained. Like her mother, doctors found tumors in Bertler’s breasts. But in her case, they were benign. “We’re walking out of the doctor’s office, and I could have kissed the sidewalk,” Bertler said. “I was so grateful.” From her experience, it became her mission to help others. Dollars for Mammograms works to remove financial barriers for men and women who need help. In 2021, Bertler experienced another health care scare herself after receiving her second dose of the Moderna vaccine. “I woke up at about 2 in the morning with extreme pain under my arm,” Bertler said. “For the next two days, even though the pain was getting better, here I am feeling my arm to make sure I don’t have any swelling.” Bertler said it was frightening because swollen lymph nodes can be a sign of breast cancer. But experts say it’s also a normal reaction to any vaccination. “The swelling of the lymph nodes is a representation of that battle being fought and your body’s immune response against that foreign entity,” said Dr. Jason McKellop, the medical director of Breastlink. “This is a normal reaction in terms of mounting a defense to the vaccination and the covid virus.” There are 20 to 40 lymph nodes located in a person’s underarm. The CDC says swelling is generally reported two to four days after vaccination. Typically, the swelling only lasts one to two days. “I thought to myself, ‘Just relax. Just relax about this,’” said Bertler, explain how she felt when her pain went away. The Society of Breast Imaging advises women to get their annual mammograms before they get the vaccine or to wait four to six weeks after getting the shot. MORE: COVID-19 Vaccine: Can It Affect Your Mammogram Results?