Vienna was the first city on the European continent where the cowpox vaccination was applied in 1799, shortly after Jenner's (1798) publication of his encouraging results in England. Nevertheless, substantial denial and distrust was evident among doctors and patients in Europe as well, particularly in Austria. The medical doctor Johann Gottfried Bremser remains well known even today among parasitologists as a pioneer of helminthological research in Austria. He founded, in Vienna, one of the richest parasitic worm collections worldwide and published perceptive papers about helminthology. But his role as a protagonist of the cowpox vaccine has been buried in oblivion. In the late 18th and early 19th centuries, Bremser worked as a medical doctor in Vienna and was influenced by the major proponents of the vaccine in Austria, Pascal Joseph Ferro, Jean de Carro, Johann Peter Frank and others. Beyond his practical contribution as vaccinator, he excelled as a propagandist, mainly through his publications on cow pox vaccination. Bremser used his expert knowledge and sophisticated argumentation to prompt people to accept the prophylactic treatment, especially for their children. He argued for an obligatory cowpox vaccination for all. On one hand, his argumentation summarizes the contrarian opinions of that time, on the other hand the discussion shows striking analogies with the controversies of today. In a way, Bremser's commitment was a forerunner for future health policies that led to vaccination laws and ultimately to the eradication of smallpox worldwide in the second half of the 20th century.