Why Frank didn't seem sick ?
I wondered this after i saw the other characters developing symptoms pretty soon after the initial infection, so this virus was a type with short incubation period.
Bobby was showing signs of infection short after the little girl coughed , Brian aswell had shown signs of symptoms after he was infected by Bobby.
The father, Frank was with his little girl and without any mask or other safety measures and when they met with them the girl was sick for about a week.
So how Frank didn't get infected in all this time spent close to his child ?