Soon after COVID-19 vaccinations began in late 2020 and early 2021, radiologists noticed unilateral axillary adenopathy in women who had recently received their COVID-19 vaccine. In those cases, researchers recommended follow-up targeted ultrasound ranging from 4-12 weeks after the patient’s second vaccination.
Researchers from the Baylor University Medical Center wanted to learn the percentage of unilateral axillary adenopathy related to COVID-19 vaccinations. The detection of lymphadenopathy during screening mammography or mammography requested by a patient who detects a swollen lymph node prompts follow-up costs and patient anxiety.
The research team was led by Dr. Sean Raj. Dr. Raj and his researcher team members also expressed concern over the impact to the U.S. healthcare system, “Further, it represents wasted healthcare resources in the form of primary care office visits, additional visits to referring physicians, and follow-up.”
Specifics of the Research
The research team examined data on 1,027 women from December 14, 2020, to April 14, 2021. Any women with prior baseline lymphadenopathy or prior diagnosis of cancer were not included. They found that 43 women experienced unilateral lymphadenopathy — 34 of them had COVID-19 vaccination ipsilateral to the lymphadenopathy.
- 2% of women receiving the Pfizer vaccine — average age 59.7 years old.
- 5% of the women who received the Moderna vaccine — average age 63.7 years old.
- Only 1.2% of unvaccinated women experienced unilateral axillary lymphadenopathy.
- Unilateral axillary lymphadenopathy was most likely when vaccination was within 7 weeks before mammography.
- Lymphadenopathy from either vaccine resolved in an average of 46.5 days after their second dose. Women who received the Pfizer vaccine required 50.7 days to clear the lymphadenopathy, while Moderna recipients only required 41.5 days.
Lymphadenopathy will likely be detected on other types of imaging, including breast MRIs, ultrasounds, CT scans, and X-rays.
Researchers noted that future research could sample a larger population and include the Johnson and Johnson vaccine, which was unavailable to women in the study timeframe.
Recommendations Going Forward
Knowledge is power. Be sure to communicate these results to every staff member who works directly in breast cancer screening. From mammography scheduling and the mammography technologists to your radiology staff members, educate, educate, educate — to help avoid costly follow-up and unnecessary anxiety for the patients.
Screening mammography should always be scheduled around COVID-19 vaccinations.
Screening mammography should be scheduled before receiving vaccination or 8 weeks after completion of COVID-19 vaccination. Special attention should be given to women at high-risk for breast cancer. Delays of 8 weeks in screening might not be an acceptable risk for these women.
Whenever possible, include in the patient’s intake records, which vaccine women received as the Moderna vaccine appears to produce a more robust immune response in older women.
Dr. Raj anticipates that women receiving COVID boosters may have a similar reaction. He notes that one question remains about COVID boosters — will booster shots produce a similar rate of axillary lymphadenopathy, or will rates be higher or lower for women who already have a “primed” immune system?