Three U.S. studies suggest COVID-19 vaccines offer strong protection against hospitalization and death, even in the face of the highly transmissible Delta variant, but vaccine protection appears to be waning among older populations, especially among those 75 and older.

U.S. data on hospitalization from nine states during the period when the Delta variant was dominant also suggests that the Moderna vaccine was more effective at preventing hospitalizations among individuals of all ages than vaccines from BioNTech-Pfizer or Johnson & Johnson.

In that study of more than 32,000 visits to urgent care centers, emergency rooms and hospitals, Moderna's vaccine was 95 percent effective at preventing hospitalization compared with 80 percent for Pfizer and 60 percent for J&J.

Overall, the findings, released on Friday in the U.S. Centers for Disease Control and Prevention's weekly report on death and disease show that vaccines continue to offer strong protection from COVID-19.