A 62-year-old man who claims to have received 217 COVID-19 vaccinations shows no signs of adverse events linked to the shots and appears to have stronger immunity against the virus than others, researchers said as they cautioning others to not get more than the recommended vaccinations.

In a study published Monday in the journal Lancet Infectious Diseases, researchers in Germany said they were surprised by the findings, expecting the mans immune cells to be less effective after becoming used to the antigens administered through eight different vaccines.

Over all, we did not find any indication for a weaker immune response, rather the contrary, Katharina Kocher, one of the leading authors of the study, said in a news release.