Strengthening the influenza vaccine virus selection and development process

Abstract

Despite long-recognized challenges and constraints associated with their updating and manufacture, influenza vaccines remain at the heart of public health preparedness and response efforts against both seasonal and potentially pandemic influenza viruses. Globally coordinated virological and epidemiological surveillance is the foundation of the influenza vaccine virus selection and development process. Although national influenza surveillance and reporting capabilities are being strengthened and expanded, sustaining and building upon recent gains has become a major challenge. Strengthening the vaccine virus selection process additionally requires the continuation of initiatives to improve the timeliness and representativeness of influenza viruses shared by countries for detailed analysis by the WHO Global Influenza Surveillance and Response System (GISRS). Efforts are also continuing at the national, regional, and global levels to better understand the dynamics of influenza transmission in both temperate and tropical regions. Improved understanding of the degree of influenza seasonality in tropical countries of the world should allow for the strengthening of national vaccination policies and use of the most appropriate available vaccines. There remain a number of limitations and difficulties associated with the use of HAI assays for the antigenic characterization and selection of influenza vaccine viruses by WHOCCs. Current approaches to improving the situation include the more-optimal use of HAI and other assays; improved understanding of the data produced by neutralization assays; and increased standardization of serological testing methods. A number of new technologies and associated tools have the potential to revolutionize influenza surveillance and response activities. These include the increasingly routine use of whole genome next-generation sequencing and other high-throughput approaches. Such approaches could not only become key elements in outbreak investigations but could drive a new surveillance paradigm. However, despite the advances made, significant challenges will need to be addressed before next-generation technologies become routine, particularly in low-resource settings. Emerging approaches and techniques such as synthetic genomics, systems genetics, systems biology and mathematical modelling are capable of generating potentially huge volumes of highly complex and diverse datasets. Harnessing the currently theoretical benefits of such bioinformatics ("big data") concepts for the influenza vaccine virus selection and development process will depend upon further advances in data generation, integration, analysis and dissemination. Over the last decade, growing awareness of influenza as an important global public health issue has been coupled to ever-increasing demands from the global community for more-equitable access to effective and affordable influenza vaccines. The current influenza vaccine landscape continues to be dominated by egg-based inactivated and live attenuated vaccines, with a small...

High-Definition Medicine

“…From a disease prevention point of view, screening and detection of Human papillomavirus infection provides protection against the development of invasive cervical cancer (Ronco et al, 2014), detection of Heliocobacter pylori is indicative of risk for peptic ulcers (Chan et al, 2002), and hospital outbreak as well as epidemic investigations via pathogen sequencing can identify the initial source of an infection and prevent its transmission (Holmes et al, 2016; Lefterova et al, 2015). Pathogen sequencing is also being increasingly utilized in environmental monitoring applications, for example by monitoring influenza reservoirs in animal populations, identifying novel viral antigens, and ultimately informing the development of seasonal vaccines (Ampofo et al, 2015). …”

Effectiveness of the 2013 and 2014 Southern Hemisphere Influenza Vaccines Against Laboratory-confirmed Influenza in Young Children Using a Test-negative Design, Bangkok, Thailand

“…1, 7 Influenza vaccine effectiveness (VE) varies from season to season depending upon the antigenic match between circulating influenza viruses and the influenza strains represented in the vaccine, which are chosen seven to nine months prior to the current influenza season. 8 Since influenza viruses may experience antigenic drift during the influenza season, mismatches between vaccine strains and the predominant circulating viruses can occur and reduce protection from the vaccine. 9, 10 …”

The Molecular Determinants of Antibody Recognition and Antigenic Drift in the H3 Hemagglutinin of Swine Influenza A Virus

“…The distance between viruses in the antigenic map is measured in antigenic units (AU), and 1 AU is equivalent to a 2-fold dilution in the HI assay. An antigenic distance of 2 AU is considered significant, and an 8-fold HI difference (equivalent to 3 AU) is typically sufficient to consider updating the human seasonal vaccine strain (11)(12)(13). The evolution of human influenza H3N2 viruses circulating from 1968 to 2003 resulted in 11 discrete antigenic clusters of antigenically similar viruses.…”