The Delta variant and ‘breakthrough’ infections: should Americans be worried?

Experts say so-called breakthrough cases remain rare, and deaths among vaccinated people are effectively zero'

The Delta variant caused an inflection point in the battle against the Covid-19 pandemic in the United States. So-called breakthrough" cases, or Covid-19 infections in people who have already been vaccinated, upended the understanding of whether people in America needed to continue wearing masks to prevent spreading the coronavirus.

But breakthrough cases remain rare, and hospitalization and death for vaccinated people is effectively zero" in many US states reporting this data.