Breakthrough coronavirus cases after vaccines are very rare and mostly due to variants, a new CDC report found

By the end of April, more than 100 million Americans had received their coronavirus vaccines.

Clinical-trial data had indicated the vaccines would reduce the risk of getting symptomatic COVID-19 by about 66% to 95%, depending on which shot the person got. A new report from the Centers for Disease Control and Prevention suggests that was indeed the case.

Still, as of April 30, about 10,000 Americans had developed "breakthrough infections," or cases of COVID-19 diagnosed at least two weeks after they were fully vaccinated. That's a rate of about 0.01%.