Yes, PROVIRUSES is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, V 4, I 1, R 1, U 1, S 1, E 1, S 1.

Is it a valid word?

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

cDNA copy of the RNA genome of a retrovirus; the genetic material of a virus as incorporated into and able to replicate with the genome of a host cell