tetano
Editor, Senior Moderator
Vaccine
. 2026 Aug 17:91:129048.
doi: 10.1016/j.vaccine.2026.129048. Online ahead of print.
A novel candidate vaccine virus derived from Japan's first mammalian case of clade 2.3.4.4b A/H5N1 highly pathogenic avian influenza virus
Yasushi Suzuki[SUP] 1 [/SUP], Tomoko Arita[SUP] 1 [/SUP], Masayuki Shirakura[SUP] 1 [/SUP], Noriko Kishida[SUP] 1 [/SUP], Kaori Sano[SUP] 1 [/SUP], Shinji Watanabe[SUP] 1 [/SUP], Noriyo Nagata[SUP] 2 [/SUP], Yusuke Sakai[SUP] 2 [/SUP], Naoko Iwata-Yoshikawa[SUP] 2 [/SUP], Tadaki Suzuki[SUP] 2 [/SUP], Hideki Hasegawa[SUP] 3 [/SUP], Hideki Asanuma[SUP] 4 [/SUP]
Affiliations
The development of candidate vaccine viruses (CVVs) for pre-pandemic preparedness requires attenuation of pathogenicity while maintaining immunogenicity. In this study, we developed and characterized NIID-002, a reassortant virus derived from A/Ezo red fox/Hokkaido/1/2022 (H5N1; clade 2.3.4.4b), to evaluate its suitability as a candidate vaccine. NIID-002 exhibited markedly reduced pathogenicity compared with its parental strain, while retaining broad antigenic reactivity and protein yield comparable to other clade 2.3.4.4b CVVs. In mammalian models, NIID-002 demonstrated strong attenuation, causing no lethal infection in mice and only minimal weight loss with limited viral replication in ferrets. Antisera raised against NIID-002 reacted broadly with recent wild-type H5N1 isolates, suggesting potential broad protection. Protein yield analysis confirmed a production efficiency comparable to that of other CVVs within the same clade, supporting its feasibility for large-scale vaccine manufacturing. Overall, NIID-002 fulfills the key requirements for the pandemic preparedness of CVV, combining reduced pathogenicity, broad antigenic reactivity, and adequate production efficiency. These findings highlight its potential as a candidate H5N1 vaccine and underscore the continued need for surveillance and refinement of influenza vaccine strategies to address evolving viral threats.
Keywords: Candidate vaccine virus; Clade 2.3.4.4b; Highly pathogenic avian influenza; safety test.
. 2026 Aug 17:91:129048.
doi: 10.1016/j.vaccine.2026.129048. Online ahead of print.
A novel candidate vaccine virus derived from Japan's first mammalian case of clade 2.3.4.4b A/H5N1 highly pathogenic avian influenza virus
Yasushi Suzuki[SUP] 1 [/SUP], Tomoko Arita[SUP] 1 [/SUP], Masayuki Shirakura[SUP] 1 [/SUP], Noriko Kishida[SUP] 1 [/SUP], Kaori Sano[SUP] 1 [/SUP], Shinji Watanabe[SUP] 1 [/SUP], Noriyo Nagata[SUP] 2 [/SUP], Yusuke Sakai[SUP] 2 [/SUP], Naoko Iwata-Yoshikawa[SUP] 2 [/SUP], Tadaki Suzuki[SUP] 2 [/SUP], Hideki Hasegawa[SUP] 3 [/SUP], Hideki Asanuma[SUP] 4 [/SUP]
Affiliations
- PMID: 42607626
- DOI: 10.1016/j.vaccine.2026.129048
The development of candidate vaccine viruses (CVVs) for pre-pandemic preparedness requires attenuation of pathogenicity while maintaining immunogenicity. In this study, we developed and characterized NIID-002, a reassortant virus derived from A/Ezo red fox/Hokkaido/1/2022 (H5N1; clade 2.3.4.4b), to evaluate its suitability as a candidate vaccine. NIID-002 exhibited markedly reduced pathogenicity compared with its parental strain, while retaining broad antigenic reactivity and protein yield comparable to other clade 2.3.4.4b CVVs. In mammalian models, NIID-002 demonstrated strong attenuation, causing no lethal infection in mice and only minimal weight loss with limited viral replication in ferrets. Antisera raised against NIID-002 reacted broadly with recent wild-type H5N1 isolates, suggesting potential broad protection. Protein yield analysis confirmed a production efficiency comparable to that of other CVVs within the same clade, supporting its feasibility for large-scale vaccine manufacturing. Overall, NIID-002 fulfills the key requirements for the pandemic preparedness of CVV, combining reduced pathogenicity, broad antigenic reactivity, and adequate production efficiency. These findings highlight its potential as a candidate H5N1 vaccine and underscore the continued need for surveillance and refinement of influenza vaccine strategies to address evolving viral threats.
Keywords: Candidate vaccine virus; Clade 2.3.4.4b; Highly pathogenic avian influenza; safety test.