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Should You Wait To Have a Mammogram After a Vaccine?

January 05, 2024

Some researchers are suggesting women should wait six weeks after they are given vaccines such as for the flu and COVID-19 before having their yearly mammogram. Others say go ahead and get your imaging done. So which is it?

The truth is simple. COVID-19 vaccines — and nearly any vaccine — can affect mammogram results by causing your lymph nodes to slightly increase in size, which is a normal physiological response to vaccines. The decision to postpone an appointment depends on your personal situation.

Connection Between Vaccines and Mammograms

When you get sick, your immune system revs up. The same thing happens when you get a vaccine: your immune system/lymph nodes will start producing antibodies, and this causes the nearby lymph nodes to get plump and juicy. That is called lymphadenopathy.

Result: Those lymph nodes might look larger on mammograms than they did before. When lymph nodes get bigger after a vaccine is given, it should not be worrisome. If you receive a screening mammogram and the radiologist reading the exam sees an increase in lymph node size, you might be called back for a sonogram or a diagnostic mammogram image to get a closer look.

An easy solution is to book your imaging test for six or more weeks after you receive the vaccine if you are not having breast symptoms and it is your yearly screening mammogram. Problem eliminated.

When Not To Wait

Never fool around with cancer. If you have any symptom that might indicate you have breast cancer, get that mammogram as soon as possible. Also, if you’ve let too much time pass since your last mammogram and have the opportunity to get the test done, go ahead and do it. This screening is too important to miss.

These steps will help you communicate best:

  • Tell the technician when you had your last vaccines and in which arm. The lymph nodes tend to enlarge more on the side closer to where the vaccine was injected.
  • The vaccine’s manufacturer might be worth mentioning too, as some vaccines cause the lymph nodes to flare up more than others — which isn’t bad, but the radiologist should have the facts. The same is true with the newest mRNA vaccines, which were designed to fend off the newest variants.
  • Understand that the COVID-19 vaccine does not cause cancer. It, like other vaccines, merely makes lymph nodes larger for a limited period of time.

If you are experiencing any breast related problems or symptoms, be sure to see your healthcare provider. If a mammogram or ultrasound is recommended, then go ahead and get these tests done despite having recently received a vaccine.  Some examples of concerning breast symptoms include:

  • A palpable mass (a lump you can feel)
  • A bloody nipple discharge
  • A focal area of pain in your breast

If Mammogram Shows Enlarged Lymph Nodes

If the radiologist sees a larger lymph node but no other reason for concern, you might be advised to return for an ultrasound to take a closer look at the lymph node.  Sometimes after that first ultrasound, if you provide the clinic with information regarding a recent vaccine or infection, an additional ultrasound follow-up exam in three to six months may be recommended. If your imaging exams eventually show a normal shape and size of your lymph nodes, you will know it is not cancer.

If it gets significantly larger or develops an abnormal shape, further evaluation, such as a biopsy, might be recommended. It’s best to keep up to date on all recommended vaccines that can keep you healthy, including flu and COVID-19. Just space out your mammograms accordingly — when you have no breast cancer symptoms — and you’ll have no need for concern.

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