How did Newt get the flare?

In the books, the scorch trials was another experiment set up in the desert. The subjects from two groups were supposed to reach a safe Haven and find a cure. They had been exposed to the virus through inoculation by Wicked, or they were let to believe they had been infected. When they completed the trials, "ratman" told them that the cure was still a work in progress and some of them were already immune. Most likely Newt was exposed when he became in contact with the Cranks at the Cranck settlement of Jorge and Brenda.

Newt got it when the car was flipped in the tunnel because you can see that he was being grabbed in the tunnel i have not read the books so that’s all i can tell

the Virus was airborn and he had gotten cut when the car flipped in the tunnel so the virus went through his cut and he got infected

I suppose he got it in the tunnel because after their car crashed Newt held his right arm

didn't Ava say that the virus was 'now' airborne? I didn't read the books either but I'm sure Newt didn't have a biting or scratching mark as Brenda did.

Ava said the virus was airborne, and if so, when the car flipped Newt was cut on the arm, and was infected through the wound.

i think he got it in the scorch trial when they gave him that syringe, becouse thay sat it in the main senter of the infected arm.

if you look up newt "a5 getting a syringe in the scorch trail" you will see a picture from printrest who will show u.