New CDC Data Sheds Light On Breakthrough Coronavirus Infections

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News & Politics

The new Delta variant of the novel coronavirus, which originally surfaced in India, is said to be far more transmissible than other variants, largely because it can evade antibodies from infections and vaccines.

Fully vaccinated individuals are thought to be protected against severe disease and death, even with Delta, but science shows that breakthrough cases -- where a person gets COVID-19 despite being fully vaccinated -- can still occur.

New data from Centers for Disease Control and Prevention (CDC) shows how common breakthrough infections really are.

CDC Data

According to an internal CDC document obtained by ABC News, more than 156 million Americans are fully vaccinated. Last week, around 153,000 symptomatic breakthrough cases occurred, representing approximately 0.098 of those fully vaccinated.

Asymptomatic COVID-19 infections were not included in these estimates. In addition, in May, the CDC stopped reporting asymptomatic or mild breakthrough cases, so the real number of breakthrough infections is probably higher.

However, the CDC also noted in its document that the increase in symptomatic breakthrough infections was "expected" because millions are not vaccinated and the virus is continuing to spread.

Vaccines Work

This doesn't mean coronavirus vaccines don't work, according to experts.

Matthew Ferrari, director of the Center for Infectious Disease Dynamics at Pennsylvania State University, said that "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," he continued.

"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."

Tracking COVID-19

Apart from ceasing to report mild and asymptomatic breakthrough cases, the CDC has also dramatically reduced testing.

Experts say the CDC must increase testing in order to better track COVID-19, slow down the spread of the virus and gather information about it.

In a new editorial in the Journal of the American Medical Association, for instance, the CDC was urged to "re-energize" testing because without it "the nation cannot be sure whether declining cases are a function of decreased numbers of infections or reduced numbers of tests."

Fauci Is 'Very Frustrated'

Dr. Anthony Fauci speaks at a hearing.
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Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases (NIAID), warned this week that the U.S. is "going in the wrong direction" on COVID-19.

Fauci, who also serves as President Joe Biden's chief medical adviser, said that he and other public health officials have been "pleading" with Americans to get vaccinated, but many don't want to get their shots.

The nation's top infectious diseases expert also said that top health officials are looking at imposing new mask guidelines.