Symptomatic breakthrough COVID-19 infections rare, CDC data estimates

Approximately 153,000 symptomatic, breakthrough cases, are expected to have occurred, to date, according to internal CDC data.

Although reports of breakthrough COVID-19 cases occurring among fully vaccinated Americans are garnering much attention, as the country experiences a viral resurgence, new data illustrates just how rare these breakthrough infections are likely to be, and further shows that the vast majority of those becoming severely ill are the unvaccinated. “While anecdotal cases and clusters can conjure concern around the vaccine, when put in the larger context of how many people have been vaccinated and the sheer volume of cases in the unvaccinated population, we recognize that the vaccines are working and how rare breakthroughs actually are,” said Dr. John Brownstein, the chief innovation officer at Boston Children's Hospital and an ABC News contributor. With more than 156 million Americans fully vaccinated, nationwide, approximately 153,000 symptomatic breakthrough cases are estimated to have occurred as of last week, representing approximately 0.098% of those fully vaccinated, according to an unpublished internal Centers for Disease Control and Prevention document obtained by ABC News. These estimates reflect only the adult population and do not include asymptomatic breakthrough infections. Substantial vaccination coverage amid increasing COVID-19 case rates are driving an increase in "expected" symptomatic breakthrough infections in recent weeks, the CDC wrote in the document.