It seemed that lately everyone had been getting sick.
Darry had just gotten over with a cold and Soda was just beginning to get one. Because Steve was always with Soda, naturely he caught it too. Johnny was in the middle of suffering with the flu, and was staying with them for the time being. Two-Bit and Dally had remained healthy, but the only time Two-Bit got sick was when he got a hangover, and Dally never got sick.
So did Ponyboy want to get sick? No. Being sick was icky. So luckily, he didn't get sick.
Oh no. He broke his arm.