After the coronavirus’ delta variant took root in the United States, vaccinated Americans were still 10 times less likely to be hospitalized for Covid-19 and 11 times less likely to die than unvaccinated people, the Centers for Disease Control and Prevention said Friday, a result CDC Director Rochelle Walensky cast as “further evidence of the power of vaccination.”
The CDC studied over 600,000 Covid-19 infections across 13 U.S. cities and states from April to July, and found just 8% of cases were among fully vaccinated patients.
The vaccines were slightly less effective at stopping overall infections after delta became the virus’ dominant strain: Unvaccinated people were 4.6 times more likely to catch the virus from late June to mid-July, down from 11.1 between early April and late June, and the vaccines’ effectiveness dropped from 91% to 78% over the same period.
Still, the vaccines held up against hospitalization and death, with vaccinated U.S. adults 10.4 times less likely to end up in the hospital and 11.3 times less likely to die after delta surged in late June, a slight decrease from 13.3 and 16.6 before delta’s onset.
The CDC said the vaccines were 90% effective at stopping hospitalization and 91% effective at staving off death after June, a small drop from 92% and 94% pre-delta.
Another CDC study released Friday found Moderna’s coronavirus vaccine was more effective than its peers at preventing hospital visits amid delta’s surge. Moderna’s effectiveness stood at 92%, Pfizer’s vaccine showed 77% effectiveness and Johnson & Johnson’s vaccine stood at 65%, according to data from nine states between June and August.