Dengue is the poster child for antibody dependent enhancement: The first infection is typically pretty mild, but there's 4 Dengue strains and a second infection

Dengue is the poster child for antibody dependent enhancement: The first infection is typically pretty mild, but there's 4 Dengue strains and a second infection with one of the other 3 is much more severe. The original vaccines for these had to be scrapped because they had the same effect, though current ones work against all 4 strains.