[Fomite]

Indeed, one of the criteria for being a BSL4 pathogen is either being likely to cause severe or fatal disease in humans and not having a readily available treatment.

Ebola qualifies as that regardless of its contagiousness. Similarly, one of the most contagious diseases out there, measles, does not, because it is easily vaccinated against.

[ghshephard]

Smallpox has a vaccine and is not considered a BSL4 pathogen - so, available treatment isn't the only component.

[pessimizer]

>one of the criteria for being a BSL4 pathogen is [...] not having a readily available treatment.