The Last of Us, Plausible?

The Last of us on HBO is undoubtedly a huge hit, although the show is primarily about love and how we share in it. The premise of the show is an apocalyptic event brought on by a fungal infection which turns grandmothers into crazed killers. We're all still living with the challenges Covid brought us so... how likely is it that an event like this could occur and what's out there for us to be concerned about? The Answer? There's some stuff...