Vaccines are less protective against Delta infection but still reduce risk by two-thirds, CDC study shows
By Michael Nedelman, Eric Levenson and Madeline Holcombe Vaccine effectiveness against Covid-19 infection dropped from 91% to 66% once the Delta variant accounted for the majority of circulating virus, according to a study published Tuesday by the US Centers for Disease Control and Prevention. “While we did see a reduction in the protection of the Covid-19 vaccine against the Delta variant, it’s still two-thirds reduction of risk,” lead author Ashley Fowlkes, an epidemiologist for CDC Covid-19 Emergency Response, told CNN on Tuesday. The study is in line with others from the US and around the world showing Delta’s increased tendency to