The director of admissions outreach at Clark University, Lydia Mann, says that students don’t necessarily have to avoid writing about Covid in their admissions applications:
This year, it isn’t a burden to have a COVID-19 essay added to the application. There is no “right way” to answer the prompt, and there should be no subconscious competition for whose life was most burdened by this pandemic. Every piece of writing that a student shares with us is important and worthy of our attention. Everyone should have an opportunity to show more sides of themselves in a process that allows little room for personal expression.

And, she concludes, writing in Inside Higher Ed:
There are a lot of mixed messages out there for high school seniors completing the college application this year: “Do I or don’t I provide an answer to that essay prompt about COVID-19?” I think the answer is fairly clear: do what feels right.