As of August 30, the US Centers for Disease Control and Prevention has received reports of 12,908 severe breakthrough cases of Covid-19 among fully vaccinated people that resulted in hospitalization or death.
When a fully vaccinated person becomes infected, data suggests that older adults and those with multiple underlying medical conditions are more likely to develop serious illness.
According to the CDC data, approximately 70% of breakthrough cases resulting in hospitalization were among adults 65 and older, and approximately 87% of breakthrough cases resulting in death were among adults 65 and older.
The median age of vaccinated adults with breakthrough cases that required hospitalization was 73, and approximately 71% had three or more underlying conditions, including diabetes, heart disease, autoimmune conditions, and others.
This CDC data is based on voluntary state reporting and may be incomplete, but multiple studies indicate similar trends.
Unvaccinated people make up majority of adult hospitalizations
According to a preprint study published last week by the CDC, unvaccinated adults in the United States are 17 times more likely to be hospitalized for Covid-19 than fully vaccinated adults, and patients hospitalized with a breakthrough case are older and more likely to have at least three underlying medical conditions.
According to the study, unvaccinated patients hospitalized with Covid-19 had a median age of 59 and approximately 56% had three or more underlying conditions.
Another study also found elderly people with underlying conditions accounted for most severe breakthrough cases.
“Identifying who is more likely to develop severe COVID-19 illness after vaccination will be critical to ongoing efforts to mitigate the impact of these breakthrough infections,” Dr. Hyung Chun, associate professor of cardiology at Yale School of Medicine, said in a statement about a study his team published Tuesday.
“These cases are extremely rare, but they are becoming more frequent as variants emerge and more time passes since patients are vaccinated,” he added.