Decreased Serologic Response in Vaccinated Military Recruits during 2011 Correspond to Genetic Drift in Concurrent Circulating Pandemic A-H1N1 VirusesReportar como inadecuado




Decreased Serologic Response in Vaccinated Military Recruits during 2011 Correspond to Genetic Drift in Concurrent Circulating Pandemic A-H1N1 Viruses - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Background

Population-based febrile respiratory illness surveillance conducted by the Department of Defense contributes to an estimate of vaccine effectiveness. Between January and March 2011, 64 cases of 2009 A-H1N1 pH1N1, including one fatality, were confirmed in immunized recruits at Fort Jackson, South Carolina, suggesting insufficient efficacy for the pH1N1 component of the live attenuated influenza vaccine LAIV.

Methodology-Principal Findings

To test serologic protection, serum samples were collected at least 30 days post-vaccination from recruits at Fort Jackson LAIV, Parris Island LAIV and trivalent inactivated vaccine TIV at Cape May, New Jersey TIV and responses measured against pre-vaccination sera. A subset of 78 LAIV and 64 TIV sera pairs from recruits who reported neither influenza vaccination in the prior year nor fever during training were tested by microneutralization MN and hemagglutination inhibition HI assays. MN results demonstrated that seroconversion in paired sera was greater in those who received TIV versus LAIV 74% and 37%. Additionally, the fold change associated with TIV vaccination was significantly different between circulating 2011 versus the vaccine strain 2009 of pH1N1 viruses ANOVA p value = 0.0006. HI analyses revealed similar trends. Surface plasmon resonance SPR analysis revealed that the quantity, IgG-IgM ratios, and affinity of anti-HA antibodies were significantly greater in TIV vaccinees. Finally, sequence analysis of the HA1 gene in concurrent circulating 2011 pH1N1 isolates from Fort Jackson exhibited modest amino acid divergence from the vaccine strain.

Conclusions-Significance

Among military recruits in 2011, serum antibody response differed by vaccine type LAIV vs. TIV and pH1N1 virus year 2009 vs. 2011. We hypothesize that antigen drift in circulating pH1N1 viruses contributed to reduce vaccine effectiveness at Fort Jackson. Our findings have wider implications regarding vaccine protection from circulating pH1N1 viruses in 2011–2012.



Autor: Dennis J. Faix, Anthony W. Hawksworth, Christopher A. Myers, Christian J. Hansen, Ryan G. Ortiguerra, Rebecca Halpin, David Wentw

Fuente: http://plos.srce.hr/



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