The threat of avian influenza A (H5N1). Part IV: development of vaccines

Abstract

Among emerging and re-emerging infectious diseases, influenza constitutes one of the major threats to mankind. In this review series epidemiologic, virologic and pathologic concerns raised by infections of humans with avian influenza virus A/H5N1 are discussed. This fourth part focuses on vaccine development. Several phase I clinical studies with vaccines against H5 viruses have demonstrated limited efficacy compared to seasonal influenza vaccines. To induce protective immunity two immunisations with increased amounts of H5N1 vaccine were required. Novel vaccination strategies that are egg- and adjuvant-independent, broadly cross-reactive and long-lasting are highly desirable.

Prevalence of antibodies against influenza A and B viruses in children in Germany, 2008 to 2010

“…A limitation of this study is that while the ELISAs indicate a previous infection, they provide no information about the time of infection. Antibodies to influenza virus nucleo-and matrix protein antigens fail to contribute to protection, but they indicate the presence of subtypeindependent T-cell-mediated protection [29].…”

N-acetyl-l-cysteine (NAC) inhibits virus replication and expression of pro-inflammatory molecules in A549 cells infected with highly pathogenic H5N1 influenza A virus

“…Highly pathogenic H5N1 influenza A viruses are considered to be potential progenitors of a novel influenza pandemic [1][2][3][4][5][6]. Human infections with highly pathogenic influenza A H5N1 viruses are associated with severe pneumonia, lymphopenia, high viral loads in the respiratory tract, and hyper-induction of cytokines and chemokines (cytokine storm) [7].…”

Incorporation of Membrane-Anchored Flagellin into Influenza Virus-Like Particles Enhances the Breadth of Immune Responses

“…Although the transmission of avian influenza viruses from birds to humans is a rare event, both the continuing increase of infected human cases and the high mortality rates suggest the persisting threat of an H 5 N 1 pandemic (6). There is evidence that the 1918 pandemic virus, which caused an estimated 40 million deaths, was an avian virus directly adapted to humans (53).…”

“…There is evidence that the 1918 pandemic virus, which caused an estimated 40 million deaths, was an avian virus directly adapted to humans (53). Although two classes of antiviral drugs targeting the viral matrix protein M2 and neuraminidase, respectively, are available against influenza A viruses, financial and supply limitations as well as frequent drug resistance may limit the ability to utilize these drugs for preventing a new pandemic (6,36,38,66). It is well recognized that an effective vaccine is the primary strategy for protection against an emerging pandemic (37,51,61).…”