Delta Concern Three studies published by the U.S. Centers for Disease Control and Prevention last week showed that although delta may be hastening a decline in the effectiveness of the Moderna and Pfizer-BioNTech shots at preventing SARS-CoV-2 infections, including among nursing home residents, the vaccines remained a reliable shield against hospitalization over a six-month period.
Delta can cause breakthrough infections and illness in people with lower antibody levels, said Andrew Pekosz, a professor of molecular microbiology at the Johns Hopkins University Bloomberg School of Public Health in Baltimore. “The good news is that vaccine efficacy against severe disease is still maintained," he said.