A report published Tuesday from the Centers for Disease Control and Prevention found that, based on data out of Los Angeles County, unvaccinated people are almost five times more likely be infected and over 29 times more likely to be hospitalized with Covid-19.
By examining over 40,000 Covid cases reported in Los Angeles County between May 1 and July 25, researchers found that on July 25, by which time the delta variant had become dominant, "infection and hospitalization rates among unvaccinated persons were 4.9 and 29.2 times, respectively, those in fully vaccinated persons."
“This means that vaccinated persons are much less likely to have severe illness and may only have mild symptoms,” Dr. Sharon Balter, one of the study's authors and an infectious disease director at the Los Angeles County Department of Public Health, told NBC News. “This is a great reason to get vaccinated.”
“At the same time, because vaccinated people can get Covid and may have mild symptoms, we do encourage vaccinated people to wear masks to prevent spread to unvaccinated people who may become severely ill,” Balter said.
Even as the more contagious delta variant increased from 8 percent of positive Covid cases analyzed by the department to roughly 90 percent by the end of July, researchers found that vaccines were still offering effective protection against severe symptoms.
"These infection and hospitalization rate data indicate that authorized vaccines were protective against SARS-CoV-2 infection and severe COVID-19 during a period when transmission of the Delta variant was increasing," the report said.
Angela Rasmussen, a virologist with the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Canada, said the findings appear "consistent with a lot of the data coming in: Delta causes more breakthroughs, including symptomatic breakthrough, but vaccination dramatically reduces critical illness and death."
"The vaccines are holding up where it matters most — keeping people out of the ICU and out of the morgue," Rasmussen said.
As of this week, roughly a month after the data period ended, 64 percent of Los Angeles County residents ages 12 and up are fully vaccinated, according to public health data.