This question isn't just on COVID. Isn't self-centered, self-serving or inconsiderate to study subjects LESS applicable and useful? I know difficult to predict what useful and applicable, and not, but I can talk PROBABILITIES, not absolutes. Isn't more humane and humanitarian to solve world issues like hunger illness or poverty FIRST, before doing your LESS applicable useful subjects? What if world's best ABSTRACT PURE mathematicians all focus on world issues, and we solve them more quickly?
I don't want target subjects, but ABSTRACT PURE math (not applied!!!) or art come to mind. I know What are the most esoteric yet useless fields of mathematics? - Quora
G. F. Hardy thought Number Theory, his speciality, to be completely useless. He wrote a book A Mathematician’s Apology to try to explain why he bothered with it.
Some of his proofs are now in widespread daily use - for example in securing network communications. If you are reading this on an https: page you are using his work!
There are many other examples of esoteric ‘useless’ mathematics finding real-life relevance, but Hardy is surely the best example.