The study's lead author told AAP FactCheck the claim misinterprets the findings and that they found no link between vaccines and long COVID.

Controversial US cardiologist Peter McCullough makes the claim in a Facebook video (screenshot here), citing the German study.

"This attribution of long COVID, it's really the vaccine," he says (video mark 1min 29sec).

"It's because people took the vaccine either before or after having COVID, and that's what's driving their symptoms. It's not the respiratory infection, it's the vaccine.

"The unvaccinated who end up getting Omicron, they have the least chance of long COVID. And the fully vaccinated who are getting the virus are the ones who are getting long COVID. ... The vaccines are causing long COVID."

The study's lead author, Sophie Diexer, a PhD candidate at the University Medicine Halle, told AAP FactCheck the claim distorts the results of the study on long COVID, also called PCC (post-COVID condition).

She said Dr McCullough was "making claims that I find to be a misinterpretation of our data and I do not know how he came to his conclusions".

Ms Diexer added: "In fact, we found that the highest risk of developing PCC was during the initial phase of the pandemic, when no one had yet been vaccinated."

Professor Michael Baker, an epidemiologist at the University of Otago who has spoken frequently about long COVID, also told AAP FactCheck the claim was false.

"This study provides no evidence or even suggestion that vaccination causes long COVID," Professor Baker said.

The German study - Association between virus variants, vaccination, previous infections, and post-COVID-19 risk - was published in the November 2023 issue of International Journal Of Infectious Disease.

It looked at 48,826 people to see how long COVID/PCC varied depending on previous infection and vaccination status.

Its primary conclusion was the risk of developing long COVID was significantly lower following an infection with the Omicron variant than after an infection with earlier coronavirus variants.

The study also found vaccines made no difference as to whether long COVID symptoms developed.

“Previous vaccinations played a minimal role, and previous infections (in individuals who did not develop PCC after their first infection) were associated with a much lower risk of PCC,” the study found (Page 17).

Nowhere in the study does it claim vaccines cause long COVID.

Dr McCullough makes further inaccurate claims on his website, claiming the study's data "imply the vaccines are making post-COVID syndrome worse in most analyses".

Ms Diexer said the claim unvaccinated people infected with the Omicron variant had the least chance of long COVID ignored the study’s data.

"This is incorrect," she said.

"Our study shows that the percentage of people (vaccinated or unvaccinated) who develop long COVID symptoms after an infection was lowest at the time when Omicron was prevalent."

Ms Diexer said the study took different COVID-19 variants into account and found no noteworthy difference between how unvaccinated and vaccinated people were affected by long COVID.

"However, protection against PCC starts with protection against infection and it is important to note that we could not investigate the vaccine tailored towards the Omicron variant."

Prof Baker said the Germany study had encouraging findings regarding the prevalence of the syndrome, "notably that the risk of long COVID … was lower following Omicron infection than previous variants, and lower for those with prior infections compared with those having their first infection".

Some other studies have found differing results on whether vaccination helped prevent long COVID.

A 2022 study in the Lancet medical journal found a "low grade of evidence" vaccination could reduce the risk of long COVID, while another published in 2022 in Brain, Behaviour and Immunity found "previous vaccination did not appear to be protective" of long COVID.

Dr McCullough has a long track record of spreading COVID-19 misinformation, has been sued by a former employer and disciplined by medical boards.

AAP FactCheck has debunked other claims he has made about COVID-19, as seen here, here and here.