Development of a highly purified tick-borne encephalitis vaccine : A personal historical account.

Before the advent of a vaccine, infections with tick-borne encephalitis (TBE) virus in Austria led to the hospitalization of several hundred and, due to underreporting, possibly more than thousand patients with severe neurological disease every year. In the late 1960s and early 1970s, this country had the highest recorded morbidity of TBE in Europe, but similar endemic risk areas exist in many other European countries as well as Central and Eastern Asia. In this article, I describe my personal recollections of the development of a highly purified TBE vaccine in the late 1970s, to which I contributed as a young post-doctoral scientist mentored by Christian Kunz (then director of the Institute of Virology at the Medical Faculty, University of Vienna) in a collaboration with the Austrian biopharmaceutical company Immuno. Low reactogenicity of the newly developed vaccine was a prerequisite for mass vaccination campaigns in Austria that started in the early 1980s. Because of its excellent immunogenicity, broad application of the highly purified vaccine paved the way for a dramatic reduction of the incidence of TBE in Austria, which is outstanding in Europe and referred to as an Austrian success story of immunoprophylaxis.