. The vaccine candidates currently
being fast-tracked include those based on the vesicular stomatitis
virus (Jones et al., 2005) or the chimpanzee-derived adenovirus
serotype 3 platforms (Stanley et al., 2014). Other potential vaccine
candidates slated for upcoming clinical trials include the human
adenovirus serotype 26 or 35 platforms (Geisbert et al., 2011) with
a Modified vaccinia Ankara (MVA) boost. However, the EBOV challenge
for these vaccine studies in nonhuman primates (NHPs) is
typically an IM infection with a target dose of 1000 plaque forming
units (PFU), which is designed to test whether immunization in
advance is able to protect recipients under stringent challenge conditions,
such as an accidental needlestick injury in the laboratory.
While important, this scenario may not be relevant to outbreak situations,
in which transmission between humans likely occurs
through direct contact with infected materials, such as infected
bodily fluids and tissues (Cohen, 2004) in a nosocomial setting or
during traditional burial rituals. As a result, there is an urgent need
to test whether experimental EBOV vaccines are efficacious against
a more common infection route.