Lyles earned the medal in the 200-meter race before laying on the track and motioning for water on Thursday after the race.
The Alexandria resident - who notoriously suffers from asthma - then had to be helped off the track in a makeshift wheelchair.
He later revealed that he tested positive for the virus two days earlier and has been hydrating and quarantining until the race.
Lyles finished the race milliseconds after gold medalist Letsile Tebogo, of Botswana, and fellow American Kenny Bednarek with a time of 19.70, despite having to fend off COVID-19 and the other athletes vying for his spot on the podium.
"I woke up early about 5 a.m. on Tuesday morning and I was feeling really horrible. I knew it was more than being sore from the 100," Lyles said after the race to NBC.
"Woke up the doctors and we tested and it came back as positive for COVID. My first thought was not to panic. I'm thinking I've been in worse situations. I've run with worse conditions, I felt, and we just took it day by day, tried to hydrate as much, quarantined.
"It's taken its toll for sure, but I've never been more proud of myself to be able to come out here and getting a bronze medal."
He said he never considered not running in the final.
"No. I didn't," he said. "We were just gonna try to quarantine as much as possible and stay away, not try to pass it off and just to give it my all.
"If I weren't to make it then someone else would take my spot."
Lyles will still come home happy after winning the gold in the 100-meter. He was also qualified to participate in the 4×100-meter relay for the Americans, though it is unclear if he or another sprinter will fill that spot.
"At the moment I don't know. I'm feeling more on the side of letting team USA do their thing," Lyles said. "They've proven with great certainty that they can handle it without me.
"And if thats the case, I'm perfectly fine to say 'hey go do your thing' ... You have more than enough speed to get that gold medal."
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