text: <unk>  is a disease with very low incidence in the developed world. Lack of vaccination against<unk>  is one of the biggest risk factors that predisposes<unk>  spread. In developed countries like USA, most cases are attributed to unvaccinated or incompletely vaccinated travelers from other parts of the world. Primary vaccine failure occurs in approximately 5% of individuals vaccinated with a single dose of vaccine at 12 months of age or older and also predisposes an individual to the risk of developing<unk> .
option_0: Measles risk factors
option_1: Chickenpox risk factors
option_2: Smallpox risk factors
option_3: Strep throat risk factors
option_4: Typhoid fever risk factors
option_5: Typhus risk factors
option_6: Tularemia risk factors
option_7: Hantavirus infection risk factors