Ultrasound Confirms Swollen Lymph Nodes After COVID-19 Inoculation

Swollen lymph nodes after receiving Pfizer-BioNTech COVID-19 inoculations can be confirmed via ultrasound (US), according to a study published in European Radiology.

Patients without previous infection with coronavirus showed the most increase in swelling. “According to our results, both doses of COVID-19 vaccine induced an increase of all axillary lymph node parameters with statistically significant differences, especially in coronavirus-naïve patients,” wrote Dr. Alba Cristina Igual-Rouilleault and her Spanish team from the University of Navarra Clinic.

Results showed that nearly all patients had an increase in lymph node characteristics, with 58 patients (64%) showing suspicious nodes “(types 3, 4, 5, and 6 in Bedi’s classification),” while also revealing that “vaccine-induced hyperplastic auxiliary nodes showed benign characteristics more frequently, with mild cortical thickness and preserved uniformity, and classified mostly as Bedi type 3 in both follow-ups (43% and 42%, respectively).”

All of the study participants were cancer-free, but the suspicious nodes would cause concern in patients who had recently been diagnosed with cancer. “However, in oncologic follow-ups or patients recently diagnosed with breast cancer, malignancy exclusion is required [5], even in Bedi type 3, and percutaneous US-guided needle biopsy or a short-term follow-up ultrasound is necessary. Recommendations for follow-up vary widely, ranging from several weeks to months, so further investigations are needed to clarify data-driven guidelines,” noted the team.

“[B]oth doses of COVID-19 vaccine induced a significant increase of all axillary lymph node parameters, especially in coronavirus-naïve patients, adding new insights to previous observations of local adverse effects. To properly manage US axillary lymphadenopathy in the era of COVID19 vaccination, this study may further aid in identifying subgroups of patients that need close monitoring and perhaps for developing guidelines for clinical use,” concluded the team, though they added that “further research should be performed to understand and decipher underlying mechanisms.”


Igual-Rouilleault, A.C., Soriano, I., Quan, P.L. et al. Unilateral axillary adenopathy induced by COVID-19 vaccine: US follow-up evaluation. Eur Radiol (2021). https://doi.org/10.1007/s00330-021-08309-7. Available online October 16, 2021, at https://link.springer.com/article/10.1007%2Fs00330-021-08309-7. Accessed November 1, 2021.

Allegretto, Amerigo. Ultrasound finds swollen glands on patients after COVID-19 vaccine. AuntMinnie.com October 19, 2021, at https://www.auntminnie.com/index.aspx?sec=sup&sub=ult&pag=dis&ItemID=133801. Accessed November 1, 2021.

Fig. 2 Comparative US images from one volunteer between baseline and the first and second follow-ups showing a significant gradual increment of maximum diameter, cortex, Bedi’s classification, and Doppler scale degree.
Image and caption used under Creative Commons CC-By license. Image was not modified; caption modified to include figure number. Citation is the first entry under “Sources” in the post text.