Incidence of Axillary Adenopathy After COVID-19 Vaccination May Be Lower Than Previously Thought

Nurses fill syringes with the Moderna Covid-19 vaccine at Gillette Stadium in Foxborough, Massachusetts on February 1, 2021. – Mass vaccinations against Covid-19 opened to the public at Gillette Stadium as part of the beginning of “phase two” in Massachusetts with people 75 years old and older being allowed to be vaccinated. The Gillette Stadium Mass vaccination site is a partnership between the Kraft Family, CIC Health and the Commonwealth of Massachusetts. The site initially was inoculating a few hundred people a day and is now doing 2,500 people a day and working towards doing more. (Photo by Joseph Prezioso / AFP) (Photo by JOSEPH PREZIOSO/AFP via Getty Images)
Prior data suggested the incidence may be as high as 16%.

A single-center study revealed a low rate of axillary adenopathy in women who underwent screening or diagnostic mammography within 90 days of COVID-19 vaccination. The study was published as a letter to JAMA Oncology.

The authors noted that prior data had suggested the rate of vaccine-related adenopathy could be as high as 16%, but the current study revealed a rate of 3%.

In this retrospective study, researchers assessed axillary adenopathy in 750 women who had received at least 1 COVID-19 vaccine injection fewer than 90 days prior to screening or diagnostic mammography.

Of the 750 women evaluated, 23 (3%) had axillary adenopathy, and 2 were symptomatic.

“[T]his incidence is still higher than axillary adenopathy in otherwise normal mammography, which was reported as 0.02% to 0.04%,” the authors noted.

The authors also found that the presence of symptoms was associated with abnormal imaging (P =.01) but not with age (P =.29) or the type of vaccine received (P =.70).

There was also no significant difference in the incidence of adenopathy after the first or second dose of the vaccine (P =.34).

The median time from vaccination to mammography was significantly shorter in patients with adenopathy than in those without it — 10 days and 18 days, respectively (P <.001).

Additionally, adenopathy rates decreased as days from vaccination increased — 5.3% for 1-14 days, 2.9% for 15-28 days, and 0% for more than 28 days (P =.01).

These results suggest “routine inquiring about recent history of COVID-19 vaccination is warranted,” according to the authors.

“As COVID-19 vaccination is rolling out around the world, this study offers timing considerations and possible findings for breast imaging following vaccination,” the authors concluded. 

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Robinson KA, Maimone M, Gococo-Benore DA, Li Z, Advani PP, Chumsri S. Incidence of axillary adenopathy in breast imaging after COVID-19 vaccination. JAMA Oncol. Published online July 22, 2021. doi:10.1001/jamaoncol.2021.3127

This article originally appeared on Cancer Therapy Advisor