The Last of Us is an HBO series adaptation of the well-loved video game of the same name. The video game, which was released in 2013, takes place in a post-apocalyptic world where most of the population has been wiped out by a fungal infection outbreak. The story follows Joel, a smuggler who is tasked with escorting a teenage girl named Ellie across the United States in order to find a group of resistance fighters known as the Fireflies. As Joel and Ellie make their way across the country, they encounter various survivors, both friendly and hostile, and must navigate dangerous environments while fighting off infected creatures and rival factions. Along the way, as they travel further through uncharted territory and encounter new threats, they develop a close bond.

Now I do have something to admit. I have never actually played the video game all the way through… while I have watched some gameplay in order to research the story, I only found out about The Last of Us through the recently released television show. Therefore, this article will focus only on the show, which currently has 8 episodes, with the final one set to be released on March 13, the Monday before spring break.

So let’s get back to the show. I first encountered The Last of Us through reviews and video essays I saw online and was intrigued by the gritty story and interesting characters, so much so that I decided to give it a go. Let me tell you, I’m so glad I did!

The Last of Us is widely considered a masterpiece for several reasons. First and foremost, its story is incredibly well-crafted, with complex characters, a richly developed world, and thought-provoking themes such as loss, grief, and morality. However, in this article, I’ll be diving into one key decision that Joel, one of the main characters, makes in the final episode and debunking the controversy surrounding it to see if he did in fact make the right choice!

FULL SPOILERS MOVING FORWARD! You have been warned!

Toward the end of the story, Joel eventually succeeds in smuggling Ellie to her final destination, where a group of Fireflies who are invested in finding a cure for this deadly disease is planning to use Ellie—and her immunity to it—for research and the production of a vaccine. However, when Joel discovers that they plan on killing Ellie to achieve this goal, he makes the decision to save her, therefore supposedly sacrificing the greater good for Ellie’s life. This decision sparked some controversy both in and out of the game, but today I’m going to break down a few reasons as to why Joel was 100% right in his decision to save Ellie.

To understand this idea we have to start with the zombie infection plaguing this world. This brain infection is known to come from Cordyceps, which is actually the name of a real-world genus of fungi. The idea of a Cordyceps taking over a human’s system and mind is not all that original, though, and even exists in the real world. One species of Cordyceps fungus works by infecting ants and compelling them to find a location that is ideal for the fungus to reproduce, essentially taking over the ant’s mind while it still remains conscious. So, needless to say, the fungus that spreads in The Last of Us, turning humans into ‘Clickers,’ isn’t all that far-fetched.

This brings us back to The Last of Us; the Fireflies want to use Ellie (as she is immune to this infection) and pick apart her brain in order to produce a vaccine that could save the remaining population. What do they really think is a vaccine, though?

A vaccine essentially prepares you for an infection, but does not cure it, and therefore is not going to help anybody already infected with the disease. When your body encounters a new disease or pathogen it works to kill it and keep you healthy; however, sometimes your immune system just isn’t fast enough to produce the antibodies needed to fight off the infection. Therefore, getting a vaccine starts this process a whole lot sooner by assuring your body already possesses what’s needed to fight a specific disease.

Vaccines work extremely well in wiping out disease and saving millions of people over the years; however, vaccines work in preventing viruses, not fungi…

When it comes to vaccines against fungi, humans don’t currently have any. As Professor Neil AR Gow states, “There are no vaccines against fungi, neither are there any established immunotherapies where you help the immune system to work together perhaps with an antifungal drug to achieve a better outcome.” The Cordyceps is based on a fungal infection, which is extremely different from a virus infection. While viruses hijack your cells and force them to replicate so they can make copies of themselves, fungi are plantlike organisms that get their energy from other living things. They aren’t hijacking your cells, they are foreign cells that live inside the body. As a result of this, they are actually a lot easier to treat, as drugs can directly attack the fungal cells and the fungal cells only because they aren’t mixed with our preexisting human cells. While many researchers are currently trying to develop anti-fungus vaccines, it isn’t something that exists currently. Therefore, it seems highly unlikely that a group of Fireflies with limited resources or access to medical education would be able to develop the world’s first antifungal vaccination!

What’s more, they’re going about the process the wrong way. Vaccines work by exposing your body to safe forms of pathogens so that your natural immune system can build up antibodies to fight them off if it comes into contact with the real thing. The key, therefore, to finding a vaccine would be coming up with a weaker and non-threatening version of the Cordyceps infection so that the human body would be able to build up immunity. So, in order to do this, they can look at the antibodies Ellie is naturally producing, NOT her brain. This, in fact, does not even require killing her, which would be the absolute worst decision if they really want to find a cure for this infection.

Plasma therapy is a process currently being used to fight infectious diseases, where people who had a disease can donate plasma that is filled with the antibodies their bodies built up while fighting the virus, and this plasma can then be given to other patients to help them improve their immune system and fight the disease quicker themselves.

If the Fireflies really believe that Ellie can help them fight this infection, killing her would be THE WORST idea. Instead, they could use her plasma and research her natural antibodies in order to fight the virus successfully, without the use of a vaccine.

We also find out from audio recordings during the game, and in the second game especially, that the doctor Joel kills when saving Ellie was supposedly the only one who could’ve made a vaccination; however, his knowledge of why Ellie was immune was extremely limited and as he called it, “uncertain.” Vaccines take a long time to produce, and require a lot of research and experimentation, so killing Ellie and expecting to make a vaccine straight away is virtually impossible, especially since in this post-apocalyptic world we can safely assume that preserving her body and continuing this research for such a sustained period of time would be impossible given their resources, and the fact that they may need to evacuate their base again (as we’ve seen happen over and over throughout the game).

In conclusion, Joel’s pivotal decision to save Ellie or to let her die for the Fireflies’ misguided cause is not a moral dilemma at all—there is a clear correct answer, and Joel did make that correct choice. While it is probably right that he should’ve told Ellie about his plan and given her a choice (which she later blames him for not doing), he did, in the end, make the right one, as the chance of the Fireflies successfully making a vaccination from killing Ellie and “reverse engineering a vaccine” from her brain was very, very unlikely.