It started like so many sinus infections do for Melissa Drake — with a cough and a tickle in her throat.

It was a Wednesday in early July, and by Friday, Drake was convinced that’s what she was dealing with. As someone with a compromised immune system, it’s a frequent annoyance for her.

But five days later, she lost her sense of smell — not a typical sinus infection symptom for her. A couple days after that, she began to run a fever. That never happened before with a sinus infection.

She go...