It is probably a lot higher than actual reality. The fact that the author is a political speech writer tells me that there is likely to be a bit of scare-mongering in her verbiage.
Michael
As stated in the article: They (the statistics) come from studies and reviews conducted by or for the Centers for Disease Control and Prevention, the National Institutes of Health and published in periodicals such as the New England Journal of Medicine. And since many of those infected are asymptomatic and undiagnosed, the statistics are inadequate.