The Centers for Disease Control and Prevention (CDC) said on Tuesday, May 25, that over 10,000 vaccination breakthrough infections had been reported out of over 101 million Americans who had been fully vaccinated against COVID-19 as of April 30.

In detail, among the fully vaccinated people at the time, 10,262 vaccine breakthrough infections had been reported from 46 states and territories, according to the CDC.

The median patient age was 58, and females accounted for 63% or 6,446 of the breakthrough infections.

Furthermore, 2,725 (27%) of the infections were asymptomatic, 995 (10%) of the patients were hospitalized, and 160 (2%) of the patients died.

The CDC said that although COVID-19 vaccinations are highly effective, they will not prevent all infections. Thus some breakthroughs should be expected.

“The number of COVID-19 cases, hospitalizations, and deaths that will be prevented among vaccinated persons will far exceed the number of vaccine breakthrough cases,” the agency said.

The FDA acknowledged, however, that the breakthrough number in the report is likely a considerable undercount. The national surveillance system is relying “on passive and voluntary reporting, and data might not be complete or representative.”

Many people with vaccination breakthrough infections, especially those who are asymptomatic or have very mild symptoms, may not seek testing, according to the CDC.

In addition, the CDC began tracking only those reported breakthroughs that result in hospitalization or death on May 1 instead of all reported breakthroughs. Only cases of “highest clinical and public health significance” would be notified.

Tracking and sequencing can assist in determining who is more vulnerable to the vaccine’s neutralizing effects, as well as whether specific variations can evade the vaccine’s neutralizing effects. Limiting monitoring has been questioned by scientists, who believe that casting a wider net might be more useful.

The CDC also stated that it will continue to conduct vaccine effectiveness studies in multiple locations across the United States.

The following statement on vaccinations was also included in the release: “Even though FDA-authorized vaccines are highly effective, breakthrough cases are expected, especially before population immunity reaches sufficient levels to further decrease transmission. However, vaccine breakthrough infections occur in only a small fraction of all vaccinated persons and account for a small percentage of all COVID-19 cases. The number of COVID-19 cases, hospitalizations, and deaths that will be prevented among vaccinated persons will far exceed the number of vaccine breakthrough cases.”