Vaccine FAQs: Do COVID vaccines affect mammography results?

Swollen lymph nodes are both a vaccine side effect, and a sign it's working

Purple-capped vials of COVID-19 vaccine sit in a blue tray at Sanford Health.

Swollen lymph nodes are a side effect of the COVID-19 vaccine.

They’re also a side effect of most vaccines.

‘This isn’t unusual’

Allison Clapp, M.D., is the lead interpreting physician for mammography at Sanford Health in Fargo, North Dakota.

According to Dr. Clapp, radiologists often see swollen lymph nodes on mammograms after a patient has been vaccinated.

Not just the COVID-19 vaccines, but just about every vaccine, she said.

“The flu vaccine, the shingles vaccine, and the pneumococcal vaccine. This isn’t unusual to us, and this is an expected body’s response to any vaccine,” said Dr. Clapp.

Schedule your vaccination: COVID-19 vaccines at Sanford Health

Because this is a common finding, patients shouldn’t delay getting both their yearly mammogram or the COVID-19 vaccine.

“Both are so important to your health right now, and getting preventative measures taken care of during the COVID-19 pandemic is vital. We don’t want to see people pushing that off,” she said.

Talk with your tech

If you’ve already been vaccinated, Dr. Clapp said patients should let their technologist know which arm they received their vaccine with.

“The interpreting physician can be prepared to recognize that potentially this is the cause for a patient’s large lymph nodes,” said Dr. Clapp.

There have been very few instances, but Dr. Clapp and her team have seen this in Fargo, North Dakota. When they’ve seen it they’ve “followed them up with an ultrasound.”

“Nobody has undergone a biopsy because of this. We know that these lymph nodes should go back to normal in a few weeks.”

Safe, convenient mammograms: Tour a mobile screening unit

If a patient has been vaccinated in their right arm, they’d usually only see swollen lymph nodes on the right side.

“It would be very unusual to see it on the other side. If we saw it on both arms, that’s definitely something we would want to look at. It would probably be less likely to be due to the vaccine, and something more is going on there,” said Dr. Clapp.

She said if a patient is concerned about swollen lymph nodes, even if they’ve been vaccinated, “we want to see them.”

“Sometimes, it is just us offering reassurance to them that this is likely related to your vaccine. Sometimes that vaccine is a flag to the patient, but in reality, they had something more going on for longer and they just started to feel into their armpit after the vaccine,” Dr. Clapp added.

It’s safe at Sanford

The best way to know if the swollen lymph nodes are vaccine-related or not, Dr. Clapp explained, is to come in for yearly mammograms.

She said they’ve seen a dip in the number of women getting their yearly mammogram, for fear of being in a hospital setting during the COVID-19 pandemic.

This can potentially be dangerous in the long haul.

“Anytime you hear that patients aren’t coming in, aren’t getting their screening done, it makes us nervous. The longer we wait to undergo a screening mammogram, potentially the larger the cancers are that we do detect,” she said.

Despite the pandemic, patients are safe when they come to Sanford Health, she added.

“We are taking all the measures necessary to make sure that they get a safe mammogram and get the care they need to prevent other harms.

“We are not spreading COVID within our clinic setting, or while you are getting a mammogram. Our technologists have been safe, the physicians have been safe, and our patients have been safe.”

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Posted In Coronavirus, Fargo, Frequently Asked Questions, Imaging, Immunizations

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