What disease does Sam have in ‘The Last of Us?’

Warning: the following article contains massive spoilers for The Last of Us episode five, “Endure and Survive.”

Now that we’re past the halfway mark of the first season of The Last of Us, we’ve come to know what to expect in terms of how the show is adapting the source material. So far, the most critical narrative beats have remained intact if not slightly reworked and fleshed out.

Then there’s the more pronounced changes introduced by the television show — how the cordyceps infection behaves, the introduction of new characters, and in episode five, Henry’s younger brother, Sam, being deaf. 

In the 2013 Naughty Dog title, Sam was a perfectly healthy teenage boy, roughly the same age as Ellie, whereas HBO’s version is hard of hearing and noticeably younger. A conversation happens between Joel and Henry in the underground playroom gives us a few hints about Sam’s medical background, specifically his history with leukemia, so let’s flesh that out a little. 

Sam’s leukemia in The Last of Us, explained

Leukemia is an awful and aggressive form of cancer which affects the body’s white blood cells and can be incredibly tricky to treat in the real-world, let alone twenty years after the apocalypse in The Last of Us universe. The likelihood of a child under the age of 20 surviving the disease is extremely slim. 

It’s unclear whether or not Sam was still undergoing active leukemia treatment by the time he had met Joel and Ellie or whether or not his cancer was in remission. We do know that Henry and Sam were still in touch with Edelstein (presumably the doctor who was providing Sam with his treatment) by the time Kathleen and her resistance overthrew FEDRA, so perhaps the battle was ongoing.

Is there a link between Sam’s leukemia and his hearing loss?

The show doesn’t tell us the origins of Sam’s hearing loss outright, and that is likely an intentional decision by showrunners Craig Mazin and Neil Druckmann. This wouldn’t be a first, as they also opted to withhold the exact nature of the neurodegenerative disease that ultimately led to Frank deciding to end his life.

That said, there’s every possibility that Sam was born either deaf or hard of hearing, given how adept he and Henry are with sign language. Although, it’s not unheard of for leukemia and its treatment to cause hearing loss, with studies showing that there is up to a 40 percent chance of leukemia patients experiencing some form of complication with their ears. Even though he carries a board and pencil, which may suggest this is uncharted territory, it’s most likely for the sake of people who don’t know how to sign.