A Japanese hospital study suggests a possible link between the Covid vaccine and TAFRO syndrome. Researchers stress the data cannot prove the vaccine caused the illness.

What TAFRO Syndrome Is

First, TAFRO is a very rare, life-threatening immune disorder. It can cause fever, swelling, low platelets, kidney failure, and enlarged organs. Fewer than 500 cases are diagnosed worldwide each year.

What the Japan Study Found

Next, doctors at Nagasaki University Hospital reviewed records from 2014 to 2024. They saw two severe TAFRO cases before the pandemic, then 11 from April 2020 to October 2024. Of 13 total TAFRO patients, four had a Covid vaccine within a month of symptoms. All four needed ICU care, compared with two of nine unvaccinated patients.

Expert Views and Limits

However, the authors said the study was small and cannot show causation. They suggested immune activation from infection or vaccination may trigger excess cytokines, inflammatory signals released by the immune system. The paper also noted a small rise in iMCD, a milder related condition, but none of 12 iMCD patients were vaccinated before illness. Dr Jessica Rose, not part of the study, told the outlet she believes vaccine risks deserve more scrutiny.

Finally, the authors urged doctors to watch for TAFRO signs after vaccination. They also said larger studies are needed, while still supporting boosters as protection.