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Recently, novel highly pathogenic avian influenza H5Nx viruses (clade 2.3.4.4) caused outbreaks in US poultry. We evaluated the potential of a stockpiled A(H5N1) A/Anhui/1/2005 (clade 2.3.4) vaccine to elicit cross-reactive antibody responses to these emerging viruses. Sera from subjects who received 2 doses of MF59-adjuvanted A/Anhui/1/2005, or 1 dose of MF59-adjuvanted A/Anhui/1/2005 following priming with a clade 1 vaccine were characterized by microneutralization assays and modified hemagglutination inhibition (HI) assays. Only heterologous prime-boost vaccination induced modest cross-reactive HI antibody responses to H5Nx viruses. Heterologous prime-boost may provide a more effective vaccination strategy to broaden the antibody responses to emerging viruses. [ABSTRACT FROM AUTHOR]

Background. An effective vaccine is urgently needed against the H7N9 avian influenza virus. We evaluated the immunogenicity and protective efficacy of a split-virion H7N9 vaccine with or without the oil-in-water adjuvants in ferrets. Methods. Ferrets were vaccinated with 2 doses of unadjuvanted, MF59 or AS03-adjuvanted A/Shanghai/2/2013 (H7N9) vaccine, and the induction of antibodies to hemagglutinin (HA) or neuraminidase proteins was evaluated. Ferrets were then challenged with wild-type H7N9 virus to assess the vaccine's protective efficacy. The vaccine composition and integrity was also evaluated in vitro. Results. Adjuvanted vaccines stimulated robust serum antibody titers against HA and neuraminidase compared with the unadjuvanted vaccines. Although there was a difference in adjuvanticity between AS03 and MF59 at a lower dose (3.75 µg of HA), both adjuvants induced comparable antibody responses after 2 doses of 15 µg. On challenge, ferrets that received adjuvanted vaccines showed lower viral burden than the control or unadjuvanted vaccine group. In vitro examinations revealed that the vaccine contained visible split-virus particles and retained the native conformation of HA recognizable by polyclonal and monoclonal antibodies. Conclusions. The adjuvanted H7N9 vaccines demonstrated superior immunogenicity and protective efficacy against H7N9 infection in ferrets and hold potential as a vaccination regimen. [ABSTRACT FROM AUTHOR]

Background. Previously we conducted a double-blind controlled, randomized efficacy field trial of gD-2 HSV vaccine adjuvanted with ASO4 in 8323 women. Subjects had been previously selected to be seronegative for HSV-1 and HSV-2. We found that vaccine was 82% protective against HSV-1 genital disease, but offered no significant protection against HSV-2 genital disease.Methods. To better understand the results of the efficacy study, post-vaccination anti-gD-2 antibody concentrations from all HSV infected subjects and matched uninfected controls were measured. Three models were used to determine whether these responses correlated with protection against HSV infection or disease. Similarly, cellular immune responses from a subset of subjects and matched controls were evaluated for a correlation with HSV protection.Results. Antibodies to gD-2 correlated with protection against HSV-1 infection with higher antibody concentration associated with higher efficacy. Cellular immune responses to gD-2 did not correlate with protection.Conclusions. The protection against HSV-1 infection observed in the Herpevac Trial for Women was associated with antibodies directed against the vaccine.Clinical Trials Registration NCT00057330. [ABSTRACT FROM PUBLISHER]