HBO
The Last of Us season finale finally reveals how Ellie was immune to Cordyceps
The Last of Us has finally revealed a scientific explanation behind Ellie’s immunity, and why she was the only one capable of surviving a Cordyceps bite.
We were all dying to see The Last of Us Episode 9 on HBO. Because there are endings that leave an indelible mark on our hearts, and all those who experienced it through the video game back in 2013 have been debating the outcome for a long time. We could sense what was going to happen, but we did not expect a surprise that has put an end to one of the greatest mysteries in its story: the scientific explanation for Ellie’s immunity and why she is not affected by the fungus despite having been bitten by an infected person.
Why is Ellie immune?
- WARNING: Spoilers ahead for episode 9 of The Last of Us
Episode 9 has allowed us to discover the exact reasoning behind it thanks to two moments. The first is the presentation of Anna, Ellie's mother. A character who had hardly been mentioned in a superficial way until now, and who we met in one of the most revealing scenes of The Last of Us series: Ellie's birth in an abandoned farm, while Anna herself was attacked - and bitten - by an infected while giving birth to the girl.
The infected bit Anna when Ellie was still linked to her by the umbilical cord, before she actually cut it with a switchblade, which, by the way, is the only memento Ellie has of her mother. This coincidence resulted in the baby somehow being reached by the Cordyceps, although far from causing her fatal effects, it gave her the gift of immunity.
At another point in the episode, Marlene offers Joel an explanation from a medical point of view: the exposure to the fungus was very low for the baby, despite the fact that her mother could not escape a fatal outcome. Said residual exposure gave Ellie the ability to generate a "chemical messenger" (a substance that allows cells to communicate with each other, generating a response in the recipient) able to trick Cordyceps into thinking it she’s already infected.
As you know, the infected are connected as if they were a hive mind (remember the moment when one of the many who walked in the horde approached Tess, he recognized her as one of his own and decided not to attack her). In the case of Ellie, it is not exactly like that, since some infected have tried to attack her, but they’ve bitten her once or a thousand times, and in no time she would have transformed.
Source | The Last of Us on HBO