In Germany, a 62-year-old man decided to get 217 COVID-19 vaccinations over 29 months. He explained this decision by “personal reasons”, writes Ars Technica.

This case was described in a study published in the journal The Lancet Infectious Diseases. According to the study, the man did not seem to have suffered any negative consequences from over-vaccination.

Of course, this is an isolated case, so it cannot be extrapolated to the entire population. However, the results of the study contradict the common concern among researchers that excessive exposure to vaccination can lead to a weakened immune response.

For example, some experts have expressed this concern in discussions about how often people should receive booster doses of the COVID-19 vaccine.

Experts from the Institute of Microbiology in Germany learned about the German’s story and invited him to be tested. They were able to collect blood and saliva samples from the man after the 214th and 217th doses of the vaccine. The scientists then compared his immune responses with those of 29 people who had received the standard three-dose series.

The man had never reported any side effects from vaccination, and his clinical testing showed no related abnormalities. The researchers studied his reactions to the vaccines and found that while some aspects of his protection were stronger, overall his immune responses were functionally similar to those of people who received much smaller doses.

His blood antibody levels rose after a new dose of the vaccine, but then began to decline, similar to what was seen in the control group.