Why Lymph Nodes May Swell after COVID-19 Vaccine

CLEVELAND – If you’ve received a COVID-19 vaccine, you may have noticed some swollen lymph nodes.

Believe it or not, that’s actually a good sign.

Laura Dean, MD, a breast cancer specialist with Cleveland Clinic, said it simply means your body is responding to the immunization as it should – and it’s not unusual.

“We know that lymph node swelling can be a common reaction, or side effect, to any vaccine – especially the flu vaccine or the shingles vaccine that we’ve had lots of experience with over the years,” she said. “And that seems to be especially true following the COVID vaccine.”

Dr. Dean said a small number of patients have reported swollen lymph nodes under the arm two-to-four days after vaccination, on average.

She noted, the swelling is almost always on the same side where they were vaccinated, and typically returns to normal about four weeks later.

She added that this is a common response to vaccination, in general.

However, lymph node swelling is sometimes associated with cancer, causing some people to worry.

Any time you find lumps or bumps that are concerning, Dr. Dean recommends talking it through with your health care provider for peace of mind and next steps.

“Your doctor may be able to reassure you. They may send you for imaging studies, such as an ultrasound of your lymph nodes up under your arm and then we can just kind of follow you and make sure that everything is responding as we would expect in a typical vaccine reaction,” said Dr. Dean.

If you happen to have a routine mammogram scheduled around the time of your COVID-19 vaccine, Dr. Dean encourages women to see it through and simply let your medical team know you’ve recently been vaccinated.

She said mammograms can be lifesaving and it’s important to get the screening when you’re due.