Potential cross-species transmission of highly pathogenic avian influenza H5 subtype (HPAI H5) viruses to humans calls for the development of H5-specific and universal influenza vaccines

Abstract

In recent years, highly pathogenic avian influenza H5 subtype (HPAI H5) viruses have been prevalent around the world in both avian and mammalian species, causing serious economic losses to farmers. HPAI H5 infections of zoonotic origin also pose a threat to human health. Upon evaluating the global distribution of HPAI H5 viruses from 2019 to 2022, we found that the dominant strain of HPAI H5 rapidly changed from H5N8 to H5N1. A comparison of HA sequences from human- and avian-derived HPAI H5 viruses indicated high homology within the same subtype of viruses. Moreover, amino acid residues 137A, 192I, and 193R in the receptor-binding domain of HA1 were the key mutation sites for human infection in the current HPAI H5 subtype viruses. The recent rapid transmission of H5N1 HPAI in minks may result in the further evolution of the virus in mammals, thereby causing cross-species transmission to humans in the near future. This potential cross-species transmission calls for the development of an H5-specific influenza vaccine, as well as a universal influenza vaccine able to provide protection against a broad range of influenza strains.

Abundant Intra-Subtype Reassortment Revealed in H13N8 Influenza Viruses

“…Thus, even low-pathogenic variants of the influenza virus can contribute to the emergence of new highly pathogenic variants and pose a serious threat to global health. For example, the spread of highly pathogenic H5 IAVs mostly overlaps with the distribution of H13N8 IAVs [ 37 ]. For this reason, co-infection of the same bird with two different viruses is possible, probably leading to the emergence of a new variant of the virus with unpredictable phenotypic characteristics.…”

Sustained vaccine exposure elicits more rapid, consistent, and broad humoral immune responses to multivalent influenza vaccines

“…Hydrogel-based vaccines elicited improved titers against HAs from H1N1, H3N2, and B strains from both past and future years and different regions than the homologous strains, indicating improved protection against genetic variance as the viruses continually mutate. Furthermore, adjuvanted PNP hydrogels also elicited robust responses H5, H7, and H9 strains, indicating the potential of these vaccines to provide protection against zoonotic spillover of highthreat pandemic strains to which the human population has little to no protection [8][9][10] . These results with a subunit HA vaccine formulation demonstrated the ability of the PNP hydrogel depot platform to provide controlled HA delivery and potent immune stimulation to improve the consistency of seroconversion, potency, and breadth of a multivalent influenza vaccine.…”

Inhibition of influenza A virus and SARS-CoV-2 infection or co-infection by griffithsin and griffithsin-based bivalent entry inhibitor

“…The predominant strains currently circulating globally are influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B (B/Victoria lineage) ( https://www.who.int/toolkits/flunet ). The highly pathogenic avian influenza (HPAI) A(H7N9) caused a large-scale zoonotic epidemic in 2013 ( 3 ), whereas A(H5N1) has shown extensive transmission and mutation in birds and mammals since 2021, raising serious concern of potential cross-species transmission of HPAI H5 to humans, possibly resulting in a pandemic in the near future ( 4 – 9 ).…”