About 5,800 Americans who were fully vaccinated – out of 66 million who received the shots – still became infected with COVID-19, according to the Centers for Disease Control and Prevention, which was reported on Thursday.
The infections, called breakthrough cases – or positive test results that represent at least two weeks after a person receives their final dose of coronavirus vaccine – represent about 0.008 percent of Americans who are fully vaccinated, the Wall Street Journal reports.
The federal agency found that 29 percent of the breakthrough infections were asymptomatic, while 7 percent led to hospitalization. So far, 74 people have died from breakthrough infections – but it is not clear what vaccine they received, if the patients come from high-risk groups or if there were any other circumstances that contributed to the deaths.
More than 40 percent of the breakthrough cases, which come from just 40 states, occurred in people over the age of 60, and 65 percent of those infected were women, the CDC said at the outlet.
The CDC is expected to publish findings on the breakthrough infections next week, the outlet reported.
On Thursday, the director of CDC, dr. Rochelle Walensky, on Capitol Hill, testified about what could cause the breakthrough, and said the agency is keeping a close eye on matters.
“Some of these breakthroughs are, of course, the failure of an immune response in the host, and then some of us, we’m worried it’s related to a variant that is circulating, so we’re looking at both,” Walensky said. .
Health officials said breakthrough infections are expected because none of the vaccines currently approved for distribution are 100 percent effective.
“You will always see breakthrough infections, regardless of the effectiveness of your vaccine,” said Dr. Anthony Fauci told the outlet.
‘Before people get excited about the quantitative number of infections, they need to understand what the denominator is, and we’re going to see breakthroughs in numbers that are within the effectiveness rate of 90 percent, 95 percent, 97 percent of the vaccines. ”
There are a number of reasons why people can become infected after being fully vaccinated, David Hirschwerk, a doctor in infectious diseases for the Northwell Health System, told the WSJ.
People who are older or people with an affected immune system may not be able to initiate a strong immune response to the vaccine and build up enough antibodies to prevent infections, the doctor explained.
In other situations, new variants, some of which are more transmissible, may circumvent the protection of the vaccine. And other times, a patient may be exposed to a particularly heavy viral load during a superspray event, for example, says the exhaust valve.
“The experience so far is that the vaccine is very effective and that those who have had breakthrough infections have had very mild and manageable diseases,” Hirschwerk, who treated a patient with a breakthrough infection, told the WSJ.
“That’s really what we see every season with the flu vaccine.”
The CDC plans to conduct genomic sequencing on respiratory samples taken from patients with breakthrough infections to gain a better understanding of the role that variants play and how they hold up against the vaccines.
Additional reporting by Jackie Salo