Mammogram first, COVID-19 vaccine second

Jun 24, 2021


If you’re due for your mammogram, be sure to get it before you get the COVID-19 vaccine. The natural immune response to the vaccine is causing an uptick in false positives for cancer in this important early screening. Dr. Claire Steen, Adventist Health Portland OB/GYN, explains why this matters.

Q. I've heard women are getting false positives on their mammograms after getting a COVID-19 vaccine. Should I put off getting my vaccine?

There has been an increase in mammogram findings that could be confused with cancer since rollout of Pfizer-BioNTech and Moderna COVID-19 vaccines. We suspect this is related to a common short-lived side effect of the mRNA vaccines called ‘lymphadenopathy” — swollen lymph nodes. We have not yet seen whether this occurs with the Johnson and Johnson vaccine as well, but until we have more information, the same guidelines should be applied to patients receiving this vaccine.

Lymph nodes play a part in the body's immune system and commonly swell in response to vaccines. There are lymph nodes throughout the body, including in the armpit and neck, which are closest to the vaccine injection site. The swelling typically occurs on the same side as the injection and is harmless. Most of the time, swollen lymph nodes will resolve within a few weeks after receiving the vaccine.

  • If you have not received your mammogram or your vaccine, it is best to schedule your mammogram before your first dose of the vaccine. There is no specific amount of time you have to wait after your mammogram to get your vaccine. It can even be done the same day, as long as the mammogram comes first.
  • If you have recently received either dose of the vaccine, the best way to avoid a false positive finding would be to schedule your mammogram six to 10 weeks after you complete the vaccine series. Of course, listen to your doctor's advice.
  • If you need a mammogram for a more urgent reason than routine breast cancer screening, your doctor may recommend that you do not wait this long. In this case, maintain an open line of communication with your doctor and your radiologist regarding your vaccine timing and symptoms to avoid misinterpretation of the imaging results.
Q. I'm about due for a mammogram. How can I get my mammogram arranged before I get my vaccine?

Call the Adventist Health Women's Clinic at 503-261-4423 or your primary care provider today to request your mammogram. If you have a preferred location for mammography, please let the clinic staff know. We will help you coordinate an appointment.

Q. I just had my vaccination, and I notice I have a lump in my armpit. How can I tell if it's just from the vaccine or if I should see my doctor about it?

Definitely tell your doctor if you feel a lump you have never noticed before. If you think it developed after the vaccine, especially if it feels sore and is located in your armpit on the same side as the injection, it is likely related to an immune response from the vaccine. The only way to know for sure is to give it time to resolve.

We never want you to sit around and feel worried, especially knowing the resolution of swollen lymph nodes may take weeks. If you are concerned, please call your doctor.