Thank you for the review - I'm glad you enjoyed it!
As for the allegory, I'd say my goal here was ultimately to present the importance of routine and a sense of normalcy in the face of looming disaster - climate change is certainly something I had in mind while working on this, but in reality, there's no shortage of things looming in the future to be scared of these days...
Something I also tried to convey was that, in spite of it all, life does go on, in one way or another - the infected are still 'conscious' in one way or another, and though even I don't know what's in store for the characters after the ending, what's for sure is that they're going to face it together.
It's easy to give up in the face of these looming threats and decide that there's no point in going on, that the looming disaster is far more than you could ever take - Birch and Judah both face those exact feelings in the story - but ultimately I wanted the story to show that there's value in going on, and that even when the worst does happen, it isn't necessarily the end - life goes on, after all.