The 54-year-old is now free of the virus but has suffered long-lasting damage to his organs and requires care at home.
Garraway, also 54, said: "I kind of think, not why did we have to be so badly affected, but you could also think why are we so lucky that he’s had the chance to continue and so many others haven't?"
She revealed that, as a result of a documentary that aired last year, Kate Garraway: Finding Derek, she was contacted by a doctor in the US who offered to help Draper with a new treatment he has been developing.
"It's all come about actually because of the first documentary, so this is a doctor who works in the US and he’s been working for 13 years on clinical trials of this treatment in the US and he is just at the point of waiting for approval on it," she said.
"When he saw the documentary, he had already started helping people with the impact of Covid. And he saw it and saw Derek and said 'I can help this man'."
Garraway and Draper flew out to Monterrey, Mexico, in November 2021 in order for Draper to begin the trial.
The couple will be returning for another 28-day stay next month, during which doctors will continue to monitor his brain, liver and lung function.
A follow-up documentary airing on February 22, Kate Garraway: Caring For Derek, follows Draper leaving hospital and beginning to receive round-the-clock care at home.
In a clip from the new programme, Draper is seen hugging his son in an emotional moment, which Garraway described as making her "burst into tears".
"I didn't actually see this until I watched the footage, and it's the first moment that Derek moves his arm … it makes me cry even now," she said.
"That is the first moment we’ve seen him be able to activate a movement prompted by emotion, not just someone going 'Can you just move your arm to the left or right'."
Kate Garraway: Caring For Derek airs on ITV on February 22 at 9pm.
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