"Ratchet came up with a vaccine," York counters calmly. Not just Ratchet, of course, but that's the only name that will piss Tarn off so it's the only one York bothers to give. He doesn't want to paint a target on Natasha's back, anyway. "I won't be getting sick."

Sure he's not feeling great at the moment, but that's probably just side effects of the shot.