[Izumi would be really sick if he offered Eichi a thank you, so maybe it was a test for his wellness all along! Eichi doesn't seem upset, after all.]

Unlike you, I haven't caught some strange illness. I'm as healthy as always.

[That is to say... not healthy at all. He's just as pale from overexertion as he normally is, but it's true that he's not coughing or sneezing, so at least he's not that bad! It's clear that his coughs only come when he's actively doing things.]

Is Tsukinaga-kun sick as well, to be sharing a room with you?