If i had to write a sequel i would go for something completely new a few hundred years in the future.
The fungus has evolved into forming hive like structures of the infected and actually breeding humans as lifestock inside overgrown cities so it won't run out of people to infect.
And there is a small tribe of immune humans, that are descendants of ellie who are trying to deal with this situation.
“It appeared that there had even been demonstrations to thank Big Brother for raising the chocolate ration to twenty grams a week. And only yesterday, he reflected, it had been announced that the ration was to be reduced to twenty grams a week. Was it possible that they could swallow that, after only twenty-four hours? Yes, they swallowed it.”
- George Orwell, ‘1984’
