Sarah Cannon - April 05, 2021

Vaccines are here, and we could not be more excited as they are so important as we continue to combat COVID-19. These vaccines are scientifically proven to provide a very high level of protection against becoming seriously ill by COVID-19. By now, you have likely heard that COVID-19 vaccines may cause temporary common side effects such as headaches and fever, but a recent study suggests that a small population of people who receive a COVID-19 vaccine may also experience swelling and tenderness of the lymph nodes in the armpit, also known as axillary lymph node swelling. All of these reactions are normal and predictable responses to the vaccine—they are signs of your immune system being activated which is exactly what we want.

However, because swelling in the lymph nodes may also be a possible sign of breast cancer, and could be detected during a mammogram, it has been reported that some physicians are suggesting that women postpone scheduled screening until several weeks after their final vaccine. This information can be confusing and we do not want our patients to delay vaccines or mammograms—both are incredibly important.

If you are scheduled for a mammogram nearing the time of your COVID-19 vaccine, here is what you should know:

What the data says

  • Local reactions are common after the COVID-19 vaccine, and may happen more often or with greater severity after the second dose.
  • Younger people are more likely to have any reaction compared to older people, and are specifically more likely to have significant reactions compared to older individuals.
  • Axillary swelling or pain is reported in up to 16% of younger patients after the second vaccine and up to 8.4% of older patients after their second vaccine.
  • Very few patients (<0.5%) in both groups experienced axillary swelling and tenderness that required medication or impeded activity. If a patient was going to have an issue, it tended to happen fairly quickly after the vaccine, and most reported symptoms lasting only two-three days.

What the data means

  • Local and systemic reactions related to the vaccines are real and quite common, especially in younger patients.
  • While axillary swelling and tenderness impacts a small group of people, it is still a significant number.
  • All of this is short-lived and will not cause long-term issues.

What patients should consider

Patients and their doctors should be aware of possible side effects from COVID-19 vaccines, and understand that they are normal and expected after vaccination.

Women in particular should educate themselves on how and why such a reaction might impact an upcoming screening mammogram, and time their mammogram appropriately. For example, if a woman is experiencing systemic side effects and has developed new tenderness or swelling in the axilla on the side of the vaccine, it might be reasonable to reschedule a mammogram for a few weeks later. However, women should not delay evaluation of persistent swelling of the axilla or swelling/tenderness that was occurring prior to receiving their vaccination.

Sarah Cannon’s recommendations

Sarah Cannon recognizes the importance of vaccination to bring an end to the COVID-19 pandemic. Sarah Cannon also recognizes that early detection of cancer depends on a woman’s ability to get her mammograms on schedule, without significant delays. Sarah Cannon recommends women make their mammograms a high priority. Those women who know that their mammogram is happening within a few weeks of their COVID-19 vaccination should consult with their physician about optimal timing. Mammograms are extremely important, as they can catch cancers earlier, when less treatment is necessary for a better outcome. Overall, patients should speak with their doctors if they are experiencing any side effects that may impact screening.