A Case of Cervical Lymphadenopathy After Vaccination Against COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has caused a major global healthcare crisis, and the fields of science and medicine have been engaged in a massive effort to control and prevent the resultant deaths and morbidity. Researchers and pharmaceutical companies have developed in record time vaccines against COVID-19 that are intended to be safe and effective; however, the short validation time has been a challenge for doctors and epidemiologists, especially in light of the increase in reports emerging from various parts of the world about the adverse effects of the new vaccines. Portugal's national regulatory authority, the National Authority of Medicines and Health Products (INFARMED), has recently granted approval for Pfizer-BioNTech (Pfizer Inc., New York, NY; BioNTech SE, Mainz, Germany) and Modema (Modema, Inc, Cambridge, MA) COVID-19 vaccines, and they are being rolled out to be administered among the general population. In light of this, it is important for breast surgeons, family doctors, hematologists, and radiologists to consider the effects of recent COVID-19 vaccination history as a possible cause in the differential diagnosis for patients with unilateral cervical adenopathy. The objective of this report is to present a case that involves an adverse reaction involving acute-onset cervical lymphadenopathy in a female patient that coincided with her vaccination against COVID-19, even though cervical lymphadenopathy had not been previously reported as a potential side effect of the COVID-19 vaccination. We discuss the case of a Portuguese physician with a family history of breast cancer, who developed right cervical lymphadenopathy after receiving the first dose of the COVID-19 vaccine. Lymph node growth and ultrasound changes observed in the patient over the weeks, and a lack of information on the COVID-19 vaccine's adverse effects, prompted an in-depth study to understand its etiology.