Maybe, but we don't know how these aliens spread or infect others. I have a hunch that if we were all 'sick' or 'infected', the captain would've likely had us forcibly ejected from the ship.

[ But, he'll give a nod. There's no sense in leaving until the threat was taken care of. Though, he didn't think they had a choice given that they were in space...it's entirely possible they could reach their 'destination' before those beings were. ]

If we don't get rid of those creatures before we're able to leave, it'll be a problem for us.