Don't Avoid the V: VACCINA, VACCINIA

VACCINA means "VACCINIA."

And what does VACCINIA mean:

cowpox

COWPOX, pluralized COWPOXES, is a cow disease.

So:

VACCINA, VACCINAS
VACCINIA, VACCINIAS

Dictionary.com provides a fuller definition: 1. a variant of the cowpox virus that became established in vaccines derived from cowpox-inoculated humans.

2. Pathology . an acute infection caused by inoculation with vaccinia virus as a prophylactic against smallpox, characterized by localized pustular eruptions.