Dozens of women in the UK have reported unusual breast growth after receiving Covid vaccines, according to data from the Medicines and Healthcare products Regulatory Agency.
The phenomenon, dubbed the “Pfizer boob job,” has sparked medical curiosity, though experts stress that no definitive link has been proven.
The MHRA’s Yellow Card system recorded 33 cases of breast enlargement linked to the Pfizer vaccine, 11 cases with the AstraZeneca jab, and four with Moderna. These reports are based on patient testimonies and have not been medically verified.
Doctors, however, say the reaction may be plausible, citing a rare immune response that could cause breast tissue to overgrow. This theory stems from a Canadian case where a 19-year-old woman’s breast size increased from a B cup to a triple G cup within six months of receiving two doses of the Pfizer vaccine.
The woman experienced tingling and slight growth after the first dose in September 2022, with rapid enlargement following the second dose. Despite treatments with steroids and antibiotics, her breast size did not reduce, leading her to undergo reduction surgery.
Experts believe the vaccine may have triggered a rare condition called pseudoangiomatous stromal hyperplasia (PASH), where breast tissue cells grow excessively. PASH is poorly understood and has only been documented about 200 times, with no previous vaccine links.
An ultrasound and CT scan of the Canadian woman showed swollen lymph nodes and dense blood vessels in her breast tissue, but no masses. Biopsies confirmed the growth was caused by PASH.
While the case suggests a potential connection, experts emphasize that more research is needed. “The association between the Covid-19 vaccine, PASH, and breast hypertrophy warrants further investigation to comprehend the spectrum of reactions to the vaccine,” the study authors stated.
Past research has shown that Covid vaccines can lead to swollen lymph nodes in the armpits, which might result in abnormal mammogram findings. In 2021, British health officials alerted medical staff to investigate such abnormalities as potential breast cancer symptoms and not dismiss them as vaccine side effects.
Systems like the MHRA’s Yellow Card reports allow experts to track potential side effects. However, some lawmakers have raised concerns about whether the system is proactive enough in identifying patterns.
Doctors also cautioned against dismissing patients’ concerns about vaccine side effects, stressing the importance of maintaining trust. “Although a temporal relationship does not establish causality, dismissing patient concerns can erode trust,” they wrote.
Though these cases remain rare, experts are calling for further studies to explore the potential link between Covid vaccines and conditions like PASH. Meanwhile, women experiencing similar symptoms are encouraged to report their cases to medical professionals.
