With four episodes left, The Event is heading towards the season (probable series) finale, and "Strain" sets the table for what's coming. It's not as dense in terms of total plots as last week's episode, so we see a fair amount of Sterling trying to pin Jarvis for Martinez's poisoning. Ultimately, Sterling has to bite the bullet and accept that Jarvis will get away, but realizes that the poisoned coffee got on his sleeve. For all the time spent to show that Jarvis would be getting away scot-free and would also be president, the ending was rather cheap.
Sean and Vicki do some digging around and find the body carrying the weapon. And... it's the Spanish flu! I know it killed a lot of people back in the day--almost 100 years ago--but would it be effective in light of modern medicine? My guess is that the writers fill link the flu to extraterrestrial origins, which could be cool, but flu doesn't have the shock factor of, say, a massive ray gun.
Score: 8.0/10