PHILADELPHIA, Dec. 11, 2013 /PRNewswire/ -- GlaxoSmithKline plc (LSE/NYSE: GSK) announced today that a peer-reviewed study issued online by the New England Journal of Medicine has reported that GSK's FluLaval ® Quadrivalent reduced flu cases among children ages 3-8 by 55.4% overall and lowered the risk of developing moderate-to-serious flu illness by 73.1% . This was the first large-scale clinical trial conducted specifically to review the safety and effectiveness of vaccinating children with a four-strain flu vaccine. The randomized, controlled clinical trial included 5,220 children and was one of the pivotal studies leading to the recent approval of FluLaval Quadrivalent by the U.S. Food and Drug Administration. "The U.S. Centers for Disease Control recommends all children get vaccinated each flu season. This is in response to how many children require flu-related medical care, and given that as many as 20,000 U.S. children are hospitalized each year due to complications of the flu," said Leonard Friedland, M.D., Vice President, Director Scientific Affairs and Public Health, GSK Vaccines North America. "This study provides robust safety and efficacy data on FluLaval Quadrivalent, and evidence of the clinical benefit of vaccination with FluLaval Quadrivalent as demonstrated by the prevention of moderate-to-severe cases of influenza among children." Newly available quadrivalent flu vaccines protect against all four of the flu strains that are in circulation during a flu season. Until this flu season, flu vaccines were limited to protecting against three influenza strains, and this necessitated the World Health Organization and other public health authorities to estimate each year what three strains might be predominant. Virus strains that scientists refer to as A-strains traditionally cause the most cases of flu, so two A strains have been included in seasonal flu vaccines. The other circulating strains, referred to as B-strains, derive from two distinct strain lineages. In six of the past 11 flu seasons, the B-strain included in flu vaccines was not the predominant B-strain in circulation. The new quadrivalent flu vaccines protect against both B strains, providing the broadest strain protection currently available.