Relative infectivity of hepatitis A virus by the oral and intravenous routes in 2 species of nonhuman primates.

Hepatitis A virus (HAV) is naturally transmitted by the fecal-oral route but can also be transmitted intravenously. To determine the relative infectivity of these 2 routes, an infectivity titration of a standard challenge pool of virulent HAV was performed in tamarins and chimpanzees. In both species, 1 oral dose of HAV was equivalent to 10(4.5) intravenous doses. These findings have relevance for attempts to develop live, attenuated HAV vaccines that can be administered orally.