Development of a nucleoside-modified mRNA vaccine against clade 2.3.4.4b H5 highly pathogenic avian influenza virus

Area of Science:

• Virology
• Vaccinology
• Public Health

Background:

• Highly pathogenic avian influenza (HPAI) viruses, specifically H5 clade 2.3.4.4b, are circulating globally at unprecedented levels in wild and domestic bird populations.
• These HPAI H5 viruses pose a significant threat due to their potential for adaptation and spillover to human populations, necessitating the development of effective countermeasures.

Approach:

• Development of an mRNA vaccine encoding the hemagglutinin (HA) glycoprotein from a circulating clade 2.3.4.4b H5 avian influenza virus isolate.
• Evaluation of the vaccine's immunogenicity in preclinical models, including mice and ferrets.
• Assessment of the vaccine's efficacy in protecting ferrets against challenge with a homologous clade 2.3.4.4b H5N1 avian influenza virus strain.

Key Points:

• The developed mRNA vaccine successfully elicited an immune response in both mice and ferrets.
• Vaccinated ferrets demonstrated complete protection against morbidity and mortality following a lethal challenge with the H5N1 HPAI virus.
• The vaccine's ability to prevent severe disease and death highlights its potential as a protective strategy against H5 clade 2.3.4.4b avian influenza.

Conclusions:

• The mRNA-LNP vaccine encoding the H5 HA glycoprotein is a promising candidate for controlling HPAI H5 clade 2.3.4.4b.
• This vaccine technology offers a potential strategy to mitigate the impact of widespread avian influenza outbreaks and reduce the risk of human adaptation.
• Further research and development are warranted to advance this vaccine towards clinical application for both avian and potentially human health security.