The Centers for Disease Control and Prevention changed its guidance to recommend everyone, regardless of vaccination status, wear masks in Covid-19 hot spots. A study of an outbreak in Provincetown, Massachusetts, found around three-quarters of people infected there were vaccinated. As cases increase nationwide, it’s understandable to think that breakthrough cases (infections in vaccinated people) are now a main driver of the ongoing Covid-19 surge.

But the evidence is clear: The problem is the unvaccinated population. If more people got the vaccines, the current surge wouldn’t be as big; it certainly wouldn’t lead to the levels of hospitalization and death now seen across the US. This was true months ago, and remains true today.

Unvaccinated people still make up the vast majority of cases, hospitalizations, and deaths. They’ve made up more than 94 percent of reported Covid-19 cases in states with available data, a report last week from the Kaiser Family Foundation found. They’ve also made up similar, or higher, shares of hospitalizations and deaths.

Then there’s what really happened in the Provincetown outbreak. The headlines noted three-fourths of people infected by the virus were vaccinated. But among the more than 900 cases tracked as a result of the outbreak, just seven led to hospitalization — and there were zero deaths. If this was 2020, when there were no vaccines, closer to 90 people would have been hospitalized and about nine would have died, based on hospitalization and death rates over the last year.

“The vaccines are upholding their promise to massively prevent serious disease, hospitalizations, and death,” Monica Gandhi, an infectious diseases doctor at the University of California San Francisco, told me. “That’s the main message I get from that outbreak.”

If every outbreak in the country today looked like the one in Provincetown, the coronavirus would be defanged. The virus would make a small number of people seriously ill, but, like the seasonal flu or a common cold, would mostly produce relatively mild symptoms or none at all.

Read the full article about COVID-19 variants and the vaccine by German Lopez at Vox.