title: Comparison of the trivalent live attenuated vs. inactivated influenza vaccines among U.S. military service members.
abstract: Limited effectiveness data are available comparing live attenuated influenza vaccine (LAIV) to inactivated influenza vaccine (TIV) among adults. To compare the incidence of influenza-like illness following immunization of adults with LAIV vs. TIV, we conducted a retrospective cohort analysis of active component U.S. military personnel for the 2005-2006 and 2006-2007 influenza seasons. Recruits experienced a much higher burden of disease compared to non-recruits, with crude incidence rates of influenza-like illness 2-16 times higher than non-recruits depending on the season and cohort. For both seasons, a slightly greater protection from influenza-like illness was found for non-recruits who received TIV compared to LAIV (adjusted incidence rate ratio, 1.17 (95% CI, 1.14-1.20) and 1.33 (95% CI, 1.30-1.36), 2005-2006 and 2006-2007 influenza seasons, respectively). However, for Army and Air Force recruits, LAIV was found to provide significantly greater protection from influenza-like illnesses compared to TIV, with adjusted incidence rates of influenza-like illness 22-51% and 18-47% lower among LAIV compared to TIV recipients for the 2005-2006 and 2006-2007 influenza seasons, respectively. Possible reasons for differences in recruit and non-recruit findings include differences in pre-existing influenza antibody levels, differing respiratory disease burden, and/or unmeasured confounding. Consideration of these findings should be made when developing influenza immunization policies.
authors.affiliation: Armed Forces Health Surveillance Center, U.S. Army Center for Health Promotion and Preventive Medicine, 2900 Linden Lane, Suite 200, Silver Spring, MD 20910, USA. angie.eick@us.army.mil
authors.forename: Angelia A
authors.initials: AA
authors.lastname: Eick
authors.forename: Zhong
authors.initials: Z
authors.lastname: Wang
authors.forename: Hayley
authors.initials: H
authors.lastname: Hughes
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Ford
authors.forename: Steven K
authors.initials: SK
authors.lastname: Tobler
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D012189:Retrospective Studies; D013997:Time Factors; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000276:immunology; D015164:Vaccines, Inactivated / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated