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to have occurred as of last week, representing approximately 0.098% of those fully vaccinated, according to an unpublished internal Centers for Disease Control and Prevention document obtained by ABC News.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.
Experts stress that no vaccine can provide 100% protection, but they are still very effective at preventing severe illness and death.
“The risk to fully vaccinated people is dramatically less than that to unvaccinated individuals. The occurrence of breakthrough cases is expected and, at this point, is not at a level that should raise any concerns about the performance of the currently available vaccines,” Matthew Ferrari, director of the Center for Infectious Disease Dynamics at Pennsylvania State University, told ABC News.
“Some vaccinated folks may still get infected, some may still transmit. And the more vaccinated people there are, the more breakthrough cases we’ll see,” he added.
Coronavirus cases are now at their highest point since early May, according to CDC data, with the U.S. average nearly quadrupling since June to 47,000 new cases a day, largely driven by the highly infectious delta variant, which now accounts for more than 83% of new cases nationwide.