Warning: Major spoilers ahead for 28 Years Later

Set nearly three decades after the events of 28 Days Later, the highly-anticipated sequel 28 Years Later from Danny Boyle and Alex Garland introduces new versions of the Infected that have evolved since the initial outbreak. As was the case with the franchise’s first sequel, 28 Weeks Later, 28 Years Later follows a completely new set of characters, and includes a star-studded cast featuring Aaron Taylor-Johnson, Jodie Comer, and Ralph Fiennes. The new movie follows a small family living in a protected community off the coast of the quarantined British Isles, and their dangerous and terrifying exploits on the mainland.

28 Years Later already has a sequel confirmed, but it still operates as a self-contained story despite all the setup for the next chapter that occurs. By the ending of 28 Years Later, the new reality that resulted from the thriving and adaptation of the Rage Virus had been fully realized. One of the biggest changes from the original movie is the nature of the Virus itself, and subsequently the nature of the Infected. The movie introduced several variants on the twitchy, fast Infected, although very little is revealed about their origins, meaning they may require a bit of explanation.

28 Years Later Introduces The Infected’s Alpha

The Strong, Fast, Hulking Variants Command Others

The biggest (literally and metaphorically) change to the nature of the Infected in 28 Years Later is the rise of the Alpha, an ultra-fast and ultra-strong variation on the typical Infected. There are multiple Alphas on the mainland, but they all share the same physical traits. The Alphas appear to be able to control, or at least aim, the intentions of the twitchy, sprinting Infected from the original movies, who have themselves appeared to develop more control than previously seen in the franchise. The Alphas are extremely durable, and are able to withstand attacks that would kill the lesser Infected.

Perhaps most importantly, the Alphas appear to have much more intellect and self-control than the more common twitchy variant. They direct the hunting of the Infected, and even seem to take trophies of victims in the form of their ripped-off heads with the spines still attached. While never explicitly stated, it seems likely that, like in a pack of animals, the Alpha is responsible for most of the breeding that occurs in the Infected population. To be clear, they are still vicious, they simply have more control and intellect to complement their mᴀssive size and strength.

28 Years Later’s New & Bigger Infected Explained

The Rage Virus Has Yielded Some Ghastly Variations

The other major variants of the Infected introduced in 28 Years Later are referred to as “Slow Lows” in an allusion to their method of movement. The Slow Lows are pale, obese creatures that move largely by crawling along the ground, surviving on worms, bugs, and other low-to-the-ground, easy-to-catch prey. A child version of the Slow Lows also appears, indicating that either they are also capable of breeding, or the transformation into a Slow Low occurs after an Infected is born. Their slow nature makes them easier to kill, but they are still dangerous in large numbers.

28 Years Later introduces the Slow Lows, the Alphas, and the familiar yet more coordinated fast Infected as the new reality of the British Isles, but somewhat surprisingly it doesn’t give a reason for their existence. It’s clear that the Rage Virus has mutated in the 28 years since it was first unleashed, and it now impacts individuals in different ways. Jamie notes that for the Alphas the Rage Virus acted “like steroids”, making them inhumanly strong and gigantic in stature. The real answer is likely something scientific and medical, although it’s possible we never get the full medical breakdown.

28 Years Later Includes A Pregnant Infected Too

One of the most significant evolutions of the Infected is the ability to not only become pregnant, but to become pregnant with a child who does not have the Rage Virus. As Dr. Kelson explains to Spike and Isla, the child was protected by its mother’s placenta, which did not permit the Rage Virus to infect the child in utero. The child that is brought back to Holy Island does not appear to show any symptoms of the Rage Virus, particularly not the tell-tale red eyes, but it remains to be seen if the Virus still resides inside its body.

The fact that an Infected was able to become pregnant is an indication of the level of control that at least the Alphas have over themselves. For a baby not only to be conceived, but then for the mother to receive enough nutrition for her body to sustain a pregnancy, there is seemingly enough intelligence on the part of the Alpha to ensure the pregnant Infected is taken care of. Spike, Isla and Erik discover her giving birth sequestered in a train car with the Alpha standing guard, so the pregnancy seems to be intentional, or at least welcome.

How 28 Years Later’s Infected Compare To The Previous Movies

The Fast, Twitchy Infected Are Far From The Only Threat

The Infected from 28 Days Later and 28 Weeks Later are extremely dangerous given how fast they are, and how quickly the infection can spread. Immediate death is certainly possible from an Infected attack, but a transformation due to contagion is the more likely outcome based on what’s been seen in the movies. The fast Infected of 28 Years Later don’t seem to be all that different in appearance or behavior, but they are clearly working with more organization thanks to the oversight of the Alphas that lead them.

As dangerous as the speedy variants are from a swarming standpoint, the Alphas have completely changed the nature of the Infected threat on the mainland. The Alphas are capable of planning, patience, and intentional reproduction, so they are a much more significant threat than their simpler, raging counterparts from decades earlier. It may be too much to believe that the Alphas are capable of sending a coordinated attack to Holy Island, but we have no actual idea how smart they can be, which is the scariest notion of all.

On top of their threat level, the new Infected variants’ level of intelligence makes them more sympathetic. It’s pretty clear based on the ending of 28 Years Later that the line between the Infected tearing people apart with their bare hands and Jimmy Crystal’s henchmen shredding Infected with weapons is becoming blurred. Jamie notes to Spike that the Infected have no minds thanks to the Rage Virus, and therefore no souls. It’s now incredibly clear how wrong that ᴀssessment is, and Spike’s reconciliation of that fact will play a major role in the next movie.