A 62-year-old man from Magdeburg, Germany, said he had received 217 COVID-19 vaccine doses over 29 months for "private reasons." Immunologists at Friedrich-Alexander-Universität Erlangen-Nürnberg saw a chance to test a question that had been largely theoretical: can hitting the immune system with the same vaccine over and over wear it out?
Their findings, published online in March 2024 in The Lancet Infectious Diseases, showed no sign that it had. The man's virus-fighting T cells were plentiful and still worked. But the researchers were clear about what the case does not show, and the question behind it surfaces again every fall, including now, as updated 2026 to 2027 COVID shots roll out.
