Ellie is a character in the video game “The Last of Us” who is immune to the infection that has turned most of the human population into zombie-like creatures. While the exact cause of Ellie’s immunity is not fully explained in the game, there are several theories as to why she may be immune.

Background

In “The Last of Us,” a fungal infection has spread throughout the world, turning most of the human population into zombie-like creatures known as infected. The infection is caused by a strain of the Cordyceps fungus, which is a type of parasitic fungus that infects insects and other arthropods.

The infection in humans causes the fungus to grow and spread throughout the body, eventually taking over the host’s brain and turning them into a mindless, aggressive creature. However, some humans are immune to the infection, and Ellie is one of them.

Possible Explanations for Ellie’s Immunity

There are several theories as to why Ellie may be immune to the infection in “The Last of Us.”

Genetics

One theory is that Ellie’s immunity is due to her genetics. The game suggests that Ellie’s mother was infected with the Cordyceps fungus, but that Ellie was born immune. This could indicate that Ellie inherited a genetic mutation that makes her immune to the fungus.

Some real-world research supports the idea that genetics could play a role in immunity to fungal infections. For example, a study published in the journal PLOS Pathogens in 2017 found that certain genetic variations in humans could affect susceptibility to the fungus Aspergillus fumigatus.

Environmental Exposure

Another theory is that Ellie’s immunity is due to exposure to the fungus in her environment. The game takes place in a world where the Cordyceps fungus has spread throughout the environment, and it’s possible that Ellie was exposed to a less virulent strain of the fungus that conferred immunity.

Some real-world research supports the idea that exposure to certain types of fungi could confer immunity. For example, a study published in the journal Science in 2009 found that exposure to a less virulent strain of the fungus Histoplasma capsulatum could protect mice from a more virulent strain.

Experimental Treatment

A third theory is that Ellie’s immunity is the result of an experimental treatment. In the game, Ellie reveals that she was bitten by an infected, but did not turn into one herself. It’s possible that Ellie was part of an experimental treatment that was intended to cure or prevent infection.

This theory is supported by dialogue in the game that suggests Ellie was under close observation by the military and was being transported to a research facility when the game begins.

Conclusion

While the exact cause of Ellie’s immunity is not fully explained in “The Last of Us,” there are several theories as to why she may be immune. These include genetics, environmental exposure, and experimental treatment. The game’s creators intentionally left some aspects of Ellie’s backstory ambiguous, leaving room for interpretation and speculation. Ultimately, Ellie’s immunity is an important part of the game’s story and adds an intriguing element to the post-apocalyptic world of “The Last of Us.”