A new preprint study raises concerns about vaccine efficacy against the Delta variant, and it seems like the Biden administration is getting worried. The study, conducted by the Mayo Clinic, found that the Pfizer vaccine was only 42 percent effective against infection in July. “If that’s not a wake up call, I don’t know what is,” a senior Biden official told Axios. Overall, the study found that the Moderna vaccine was 86 percent effective against infection and Pfizer’s was 76 percent; Pfizer’s was 85 percent effective against hospitalization, while Moderna’s was 92 percent. However, the vaccines’ effectiveness against infection dropped...