Yes, VACCINAS is a Scrabble word!

Letter values in Scrabble US: V 4, A 1, C 3, C 3, I 1, N 1, A 1, S 1.

Is it a valid word?

VACCINAS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a local infection induced in humans by inoculation with the virus causing cowpox in order to confer resistance to smallpox; normally lasts three weeks and leaves a pitted scar

Also: variola vaccine, variola vaccinia, variola vaccina.