64 Percent of Vaccinated People Who Get COVID Have This in Common, CDC Says
There appears to be a common thread among breakthrough cases.
Being fully vaccinated allows you to feel a sense of relief amid the waning COVID pandemic in the U.S.—you can take off your mask, no longer need to social distance, and are highly protected against getting sick. Of course, no vaccine is 100 percent effective, so there is a small chance that you could still get infected with COVID after being vaccinated, which is known as a breakthrough infection. According to the Centers for Disease Control and Prevention (CDC), there is one major commonality among these breakthrough infections: Based on new research, 64 percent of vaccinated people who get COVID are infected by variants.
The CDC released a new report on May 25 breaking down what researchers have learned so far about breakthrough infections. According to the report, more than 10,000 vaccine breakthrough infections have been reported in the U.S. as of April 30. This is out of the nearly 101 million people who had been fully vaccinated by that date.
"Despite the high level of vaccine efficacy, a small percentage of fully vaccinated persons … will develop symptomatic or asymptomatic infections with SARS-CoV-2, the virus that causes COVID-19," the CDC states.
When looking at the available sequence data from reported cases, researchers found that 64 percent of fully vaccinated people who got COVID were infected by variants of concern, including U.K. variant B.1.1.7, California variants B.1.429 and B.1.427, Brazil variant P.1, and South Africa variant B.1.351. This is similar to the CDC's estimate of total U.S. COVID cases (including those not fully vaccinated) caused by variants of concern. According to the report, these variants account for 70 percent of all COVID cases between March 28 and April 10—meaning the vaccine is similarly effective at protecting people against variants and the previously dominant COVID strain.
"Current data suggest that COVID-19 vaccines authorized for use in the United States offer protection against most variants," the CDC says. "However, some variants might cause illness in some people after they are fully vaccinated."
The researchers found that more than half of the breakthrough infections were caused by the U.K. variant, with 56 percent getting infected with B.1.1.7. But that's not particularly surprising, as the CDC says—based on current data—this variant is the most common in the U.S. right now. In comparison, 25 percent were infected with B.1.429, 8 percent were infected with B.1.427 and P.1, and 4 percent were infected with B.1.351.
If you are one of the rare people to get COVID after being fully vaccinated, your odds of a mild infection are good. According to the report, 27 percent of breakthrough infections are asymptomatic. Only 10 percent of people with breakthrough infections have had to be hospitalized—with some being hospitalized for reasons other than COVID—and only 2 percent of people with breakthrough infections have died.
"Even though a small percentage of fully vaccinated people will get sick, vaccination will protect most people from getting sick. There also is some evidence that vaccination may make illness less severe in people who get vaccinated but still get sick," the CDC says. "Despite this, some fully vaccinated people will still be hospitalized and die. However, the overall risk of hospitalization and death among fully vaccinated people will be much lower than among people with similar risk factors who are not vaccinated."