Two years ago, German doctors stumbled across news reports of a man being investigated for receiving scores of coronavirus vaccines with no medical explanation.
Then followed a flurry of speculation about what he had been up to. As it turned out, prosecutors were looking into whether he had been receiving so many extra doses as part of a scheme to collect stamped immunization cards that he could later sell to people who wanted to skirt vaccine mandates.
But to the doctors, the man was a medical anomaly, someone who had defied official recommendations and turned himself into a guinea pig for measuring the outer limits of an immune response. Last year, they asked prosecutors investigating his vaccine splurge to pass along a request: Would he like to join a research project?
Once prosecutors closed their fraud investigation without criminal charges, the man agreed.
By the time the doctors first saw him, the 62-year-old man had received 215 doses of coronavirus vaccine, they said. Flouting their pleas to stop, he received another two shots in the next months, expanding his immunological stockpile to a combined 217 doses of eight different Covid vaccine types over two and a half years.
After months of studying him, the doctors, led by Dr. Kilian Schober, an immunologist at the University of Erlangen-Nuremberg in the German state of Bavaria, reported their findings this week in The Lancet Infectious Diseases, a medical journal.
The man had seemingly never been infected with the coronavirus. He reported no vaccine side effects. And, most interestingly to the researchers, his repertoire of antibodies and immune cells was considerably larger than that of a typical vaccinated person, even if the precision of those immune responses remained effectively unchanged.
The researchers found that even the 217th shot boosted the man’s immune response. And while they were carefully looking for signs of a progressive weakening in his immune reactions over time — an unwelcome type of immune tolerance that sometimes develops during long-term viral infections — they reported seeing no such drop-off in responses.
“This indicates really how robust the immune system’s response is to such repetitive immunization,” Dr. Schober said. “Even 200 vaccinations are not nearly as much of a challenge to the immune system as a chronic infection.”
The researchers said the man was from Magdeburg, a city in central Germany, but offered few other details and said his reasons for the vaccination spree were private.
The prosecutors had collected evidence of 130 vaccinations over nine months, the researchers wrote. The man’s first vaccination, with a shot made by Johnson & Johnson, came in June 2021. Most of his subsequent shots were mRNA vaccines made by Moderna or Pfizer-BioNTech. He also received several of Pfizer-BioNTech’s updated vaccines.
In addition to their own testing, the scientists relied on the man’s routine medical tests from before and during the pandemic. But because they had no access to other vaccine hoarders, the researchers said their findings could not be used to predict how other people would react to repeated inoculations.
Other patients who are given so many doses could experience side effects, Dr. Schober said, making it unwise for people to defy medical advice to receive more than the recommended number of shots. And while the study suggested both that the vaccines were generally very safe and could continue to boost immune responses, the benefits of being repeatedly vaccinated did not necessarily outweigh the small risk of an additional shot.
For instance, Dr. Schober said, the man’s antibody levels dropped off in the periods after his most recent recorded shots, as they generally do in patients receiving the usual number of doses. The finding suggested that the man’s elevated immune response could only be kept aloft by revaccinating all the time.
“These super-high levels are not sustainable,” Dr. Schober said. “They would drop off to the normal level.”
Still, the two-and-a-half-year vaccine binge created a type of immune system stress test that doctors never would have allowed to happen on their watch. And while the results were far from conclusive, at least this one man’s immune system looked remarkably resilient.
“Two hundred vaccinations may seem like a lot,” Dr. Schober said. But immune cells capable of reacting to chronic viruses, he added, “are basically laughing” at the imitation viral particles that they have to deal with, even over the course of hundreds of shots.
