About 10-15% of people who have the Pfizer or Moderna vaccine get enlarged lymph nodes under their arm. Breast cancer can also cause swollen nodes under the arm. Because of this, many women have questions and concerns about getting incorrect mammogram results.
I have swollen lymph nodes under my arm. How do I know if this is breast cancer or a reaction to the COVID-19 vaccine?
You can't know. Enlarged lymph nodes under the arm show up in about 10-15% of people after getting vaccinated for COVID-19. They're also a sign of breast cancer. Only with mammograms or other screening tools can we know for sure what you have.
Do both COVID-19 vaccines cause swollen lymph nodes?
Yes. About 10-15% of people who get either the Pfizer or the Moderna vaccine get bigger lymph nodes under the arm.
I've had my COVID-19 vaccine. Should I wait before getting a screening mammogram?
You can. Schedule your screening mammogram 4-6 weeks after your second dose of the COVID-19 vaccine. If you choose not to wait, just know that you could have enlarged lymph nodes that need more testing.
I've heard that the COVID-19 vaccine can cause a false positive on a mammogram. How can I avoid that?
To avoid possible extra tests, you can either schedule your screening mammogram:
- Before your first dose of the vaccine
- Or 4-6 weeks after the second dose
If you need a diagnostic mammogram, don't wait. You need a diagnostic mammogram if you have a:
- Breast cancer symptom
- Current breast problem
- Recent abnormal mammogram
We'd rather catch breast cancer early than miss it just to avoid having to do an extra test.
My recent mammogram results came back abnormal. This means I have to get another test. But I know the COVID-19 vaccine can mess up mammogram results. Should I wait?
No, don't wait. If your mammogram has abnormal results or shows enlarged lymph nodes, get the recommended diagnostic testing. Catching breast cancer as early as possible is your best bet for beating it.
What is a diagnostic mammogram?
A diagnostic mammogram produces additional, more exact images than a regular mammogram. If you have abnormal screening mammogram results, diagnostic imaging will help us figure out if you have cancer or not. These can also include breast ultrasound.
I'm not sure what to do.
Talk to your primary care provider. They can provide guidance on how to lower your risk.