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.

“The vast, vast, vast, vast, vast majority of breakthrough cases end up being no more serious than the flu and typically much less than that, less than a cold and a flu,” said professor Nir Menachemi, chair of the health policy and management department at the Indiana University Richard M Fairbanks School of Public Health, and an expert in hospital surge capacity, emergency preparedness and public health administration.