Covid-19 is not one disease.

We are using vaccines differently now. That's okay, but there are implications.

When the Covid-19 vaccines were rolled out in early 2021, something remarkable happened. Over a period of a few months, as the vaccine reached more people, I began to stop seeing Covid-19 patients in the ER. At some point in late spring, there were none. Period. No deaths. No hospitalizations. Not even positive cases we sent home. The disease had vanished.

I wasn’t sure if that was the end, but I deleted a sentence in a draft of a New York Times opinion piece I published urging people to go to live arts events. The sentence had said “This may be the end, but more likely it is a window. Go to the opera now, while you can.” I should have kept that sentence.

Weeks later, the Delta variant had swept the nation. Months later it was Omicron. For high risk people (or those closely connected to them), the window had indeed closed.

As cases began to again appear in my ER, though, I noticed something different. Sick patients with positive SARS-CoV-2 tests were back, but that horrible “classic” Covid-19 pneumonia x-ray was mostly not. I saw many sick patients, but the clinical presentation was different.

Before, Covid-19 had mostly been one disease. Now it was masquerading as many.