New Analysis Reports Lower Rates of Serious Cardio-Respiratory Events Among Study Participants Administered Higher-Dose Influenza Vaccine

August 26, 2015, 2015 /PRNewswire/ -- Sanofi Pasteur, the v

accines division ofSanofi, announced that Vaccine published positive results from a new analysis of data from a large-scale, multi-center efficacy trial.

In this new analysis, researchers observed significantly fewer serious cardio-respiratory events possibly related to influenza ("the flu") in study participants 65 years of age and older who received a higher-dose split-virus inactivated influenza vaccine (IIV-HD) compared to a standard-dose split-virus inactivated influenza vaccine (IIV-SD).

In the efficacy trial, a total of 31,989 adults 65 years of age and older were randomly assigned in a 1:1 ratio to receive either IIV-HD (Fluzone® High-Dose vaccine, Sanofi Pasteur, Swiftwater, PA) or IIV-SD (Fluzone vaccine, Sanofi Pasteur) and followed for six to eight months post-vaccination for the occurrence of influenza and serious events, including events leading to death or hospitalization (or its prolongation), or events considered life-threatening or medically important, or resulting in disability. For the supplementary analysis reported in Vaccine, cardio-respiratory events were grouped into seven categories: pneumonia, asthma, chronic obstructive pulmonary disease (COPD) or bronchial events, influenza (laboratory-confirmed influenza diagnosed outside of normal study procedures), other respiratory events, coronary artery events, congestive heart failure, and cerebrovascular events.

The primary results from the efficacy trial were published in The New England Journal of Medicine, which reported that IIV-HD was 24.2 percent (95% confidence interval [CI], 9.7 to 36.5) more effective in preventing laboratory-confirmed influenza-like illness compared to IIV-SD.i In the current supplementary analysis of the trial, investigators reported that the rate of serious cardio-pulmonary events possibly related to influenza was 17.7% lower in the IIV-HD group (26.7 cases per 1000 person-seasons) compared to the IIV-SD group (32.5 cases per 1000 person-seasons). In addition, serious pneumonia was observed at a 39.8% lower rate among IIV-HD recipients (4.4 cases per 1000 person-seasons) compared to IIV-SD recipients (7.4 cases per 1000 person-seasons). The rate of hospitalization (any cause) was 6.9% lower in the IIV-HD group (95.7 cases per 1000 person-seasons) compared to the IIV-SD group (102.7 cases per 1000 person-seasons). 

"Influenza and pneumonia combined is the seventh leading cause of death in older adults in this country," ii said David P. Greenberg, MD, Vice President, Scientific & Medical Affairs, and Chief Medical Officer, Sanofi Pasteur US. "The results of this analysis focused on serious cardio-respiratory events and hospitalizations, and support the previously reported findings of the large efficacy study, in which lower rates of laboratory-confirmed influenza were observed following use of the higher-dose vaccine compared to the standard-dose vaccine among the seniors who participated."