tetano
Editor, Senior Moderator
Vaccine. 2011 Nov 10. [Epub ahead of print]
Safety and immunogenicity of two different doses of a Vero cell-derived, whole virus clade 2 H5N1 (A/Indonesia/05/2005) influenza vaccine.
Tambyah PA, Wilder-Smith A, Pavlova BG, Barrett PN, Oh HM, Hui DS, Yuen KY, Fritsch S, Aichinger G, Loew-Baselli A, van der Velden M, Maritsch F, Kistner O, Ehrlich HJ.
Source
National University Hospital, 5 Lower Kent Ridge Road, Singapore.
Abstract
A successful vaccine development strategy for areas with clustered H5N1 events requires conduct of vaccine trials in potentially non-na?ve subjects and evaluation of post-vaccination responsiveness. An open-label, randomized, phase I/II study therefore assessed the immunogenicity and safety of two different dose levels of an inactivated, non-adjuvanted, whole virus clade 2.1 (A/Indonesia/05/2005) H5N1 Vero cell-derived influenza vaccine in healthy adults (21-45 years) from a region where the virus has been circulating (Hong Kong) as well as Singapore. Subjects (N=110) were randomized 1:1 to receive two vaccinations with either 3.75μg or 7.5μg H5N1 haemagglutinin antigen 21 days apart. Safety, immunogenicity (microneutralization [MN] and single radial haemolysis [SRH] at baseline and post-vaccination) and cross-reactivity against a heterologous clade 1 strain (A/Vietnam/1203/2004) of the vaccine were assessed. Pre-existing immunity to the vaccine strain was 14% which is higher than previously reported for these regions. Two vaccinations with either vaccine formulation induced high seroprotection rates (MN titre≥1:20) against the vaccine strain A/Indonesia/05/2005: 82.7% and 86.5% in the 3.75μg and 7.5μg dose groups. Seroconversion rates and fold increase exceeded the CPMP criterion of >40% and >2.5 for MN and SRH in both dose groups after the second vaccination, while the seroprotection rate in the 7.5μg dose group determined by SRH was only marginally lower (69.2%) than the CPMP criterion of >70%. Thus, 11 of 12 CHMP criteria were fulfilled. A cross-reactive antibody response against the heterologous A/Vietnam/1203/2004 strain was demonstrated after the second vaccination (>21% by MN and ≥25% by SRH). Persistence of antibodies against the vaccine strain was also demonstrated 6 months after the first vaccination, indicating that a booster vaccination would be effective in those who have received two priming doses. No serious adverse events were reported. The H5N1 influenza vaccine against clade 2.1 strain A/Indonesia/05/2005 was well tolerated and immunogenic after two vaccinations, and induced a cross-neutralizing antibody response, with no dose effect.
Copyright ? 2011 Elsevier Ltd. All rights reserved.
PMID:
22080174
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22080174
Safety and immunogenicity of two different doses of a Vero cell-derived, whole virus clade 2 H5N1 (A/Indonesia/05/2005) influenza vaccine.
Tambyah PA, Wilder-Smith A, Pavlova BG, Barrett PN, Oh HM, Hui DS, Yuen KY, Fritsch S, Aichinger G, Loew-Baselli A, van der Velden M, Maritsch F, Kistner O, Ehrlich HJ.
Source
National University Hospital, 5 Lower Kent Ridge Road, Singapore.
Abstract
A successful vaccine development strategy for areas with clustered H5N1 events requires conduct of vaccine trials in potentially non-na?ve subjects and evaluation of post-vaccination responsiveness. An open-label, randomized, phase I/II study therefore assessed the immunogenicity and safety of two different dose levels of an inactivated, non-adjuvanted, whole virus clade 2.1 (A/Indonesia/05/2005) H5N1 Vero cell-derived influenza vaccine in healthy adults (21-45 years) from a region where the virus has been circulating (Hong Kong) as well as Singapore. Subjects (N=110) were randomized 1:1 to receive two vaccinations with either 3.75μg or 7.5μg H5N1 haemagglutinin antigen 21 days apart. Safety, immunogenicity (microneutralization [MN] and single radial haemolysis [SRH] at baseline and post-vaccination) and cross-reactivity against a heterologous clade 1 strain (A/Vietnam/1203/2004) of the vaccine were assessed. Pre-existing immunity to the vaccine strain was 14% which is higher than previously reported for these regions. Two vaccinations with either vaccine formulation induced high seroprotection rates (MN titre≥1:20) against the vaccine strain A/Indonesia/05/2005: 82.7% and 86.5% in the 3.75μg and 7.5μg dose groups. Seroconversion rates and fold increase exceeded the CPMP criterion of >40% and >2.5 for MN and SRH in both dose groups after the second vaccination, while the seroprotection rate in the 7.5μg dose group determined by SRH was only marginally lower (69.2%) than the CPMP criterion of >70%. Thus, 11 of 12 CHMP criteria were fulfilled. A cross-reactive antibody response against the heterologous A/Vietnam/1203/2004 strain was demonstrated after the second vaccination (>21% by MN and ≥25% by SRH). Persistence of antibodies against the vaccine strain was also demonstrated 6 months after the first vaccination, indicating that a booster vaccination would be effective in those who have received two priming doses. No serious adverse events were reported. The H5N1 influenza vaccine against clade 2.1 strain A/Indonesia/05/2005 was well tolerated and immunogenic after two vaccinations, and induced a cross-neutralizing antibody response, with no dose effect.
Copyright ? 2011 Elsevier Ltd. All rights reserved.
PMID:
22080174
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22080174