Data from clinical trials comparing Fluzone to Fluzone High-Dose among persons aged 65 years or older indicate that a stronger immune response (., higher antibody levels) occurs after vaccination with Fluzone High-Dose. Whether or not the improved immune response leads to greater protection has been the topic on ongoing research. A study published in the New England Journal of Medicine indicated that the high-dose vaccine was % more effective in preventing flu in adults 65 years of age and older relative to a standard-dose vaccine. The confidence interval for this result was % to %. A separate study published in The Lancet Respiratory Medicine reported that Fluzone High-dose was associated with a lower risk of hospital admissions compared with standard-dose Fluzone for people aged 65 years or older, especially those living in long-term care facilities. The study compared hospitalization rates among more than 38,000 residents of 823 nursing homes in 38 states during the 2013-14 flu season.