A 62-year-old man in Germany intentionally got 217 doses of COVID-19 vaccines within 29 months. The vaccinations occurred outside of a clinical study, and after hearing about the "hypervaccinated" man, medical researchers in Germany reached out to him to run tests.

The researchers first learned about the man, who they say got the vaccines "deliberately and for private reasons," when a public prosecutor in Magdeburg, Germany, opened a fraud investigation, according to a paper published in The Lancet Infectious Diseases medical journal on Monday. The prosecutor confirmed 130 of the vaccinations and ultimately did not file criminal charges against the man.

The researchers sent a proposal to the man and the prosecutor saying they wanted to investigate the potential impact on his immune system from getting so many of the shots.

The man voluntarily gave them blood and saliva samples and the researchers compared his antibody levels to a control group of 29 people who had three doses of mRNA COVID-19 vaccines, according to the study. 

They were able to measure the man's antibody levels after his 214th vaccination and found them highest on that day and again three days after his 215th vaccination. His contraction kinetics — the cell response to the antibodies — mirrored those of the control group. His 217th vaccination showed just a modest increase in antibodies.

They checked the levels of a variety of types of cells involved in immune system responses, and while some were boosted as his vaccinations increased, many levels were in line with the control group.

The researchers say the man appeared to suffer no significant side effects despite the extreme number of doses.

"In summary, our case report shows that SARS-CoV-2 hypervaccination did not lead to adverse events and increased the quantity of spike-specific antibodies and T cells without having a strong positive or negative effect on the intrinsic quality of adaptive immune responses," the study reads. "While we found no signs of SARS-CoV-2 breakthrough infections in [the man] to date, it cannot be clarified whether this is causally related to the hypervaccination regimen."

"Importantly, we do not endorse hypervaccination as a strategy to enhance adaptive immunity," they note.

Staying up to date with COVID-19 vaccinations is recommended for everyone ages 6 months and older in the U.S. There are three types of COVID-19 vaccines available in the U.S. — two mRNA vaccines from Moderna and Pfizer, and a protein subunit vaccine from Novavax — and there is no preferential recommendation of one over the other, according to the CDC. The CDC has a table with information on the number of recommended doses based on your past vaccinations.

The CDC recently amended its COVID-19 guidelines, shortening the 5-day isolation period and updating its guidance on masks and testing. The new recommendations offer a "unified, practical approach to addressing risk" from COVID as well as other infections like the flu and RSV, the agency said.

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• COVID-19 Vaccine

Caitlin O'Kane is a New York City journalist who works on the CBS News social media team as a senior manager of content and production. She writes about a variety of topics and produces "The Uplift," CBS News' streaming show that focuses on good news.