Universal influenza virus vaccines: what needs to happen next?

ABSTRACT

Introduction: Influenza occurs worldwide and causes significant disease burden in terms of morbidity, associated complications, hospitalizations, and deaths. Vaccination constitutes the primary approach for controlling influenza. Current influenza vaccines elicit a strain-specific response yet occasionally exhibit suboptimal effectiveness. This review describes the limits of available immunization tools and the future prospects and potentiality of universal influenza vaccines.

Areas covered: New ‘universal’ vaccines, which are presently under development, are expected to overcome the problems related to the high variability of influenza viruses, such as the need for seasonal vaccine updates and re-vaccination. Here, we explore vaccines based on the highly conserved epitopes of the HA, NA, or extracellular domain of the influenza M2 protein, along with those based on the internal proteins such as NP and M1.

Expert opinion: The development of a universal influenza vaccine that confers protection against homologous, drifted, and shifted influenza virus strains could obviate the need for annual reformulation and mitigate disease burden. The scientific community has long been awaiting the advent of universal influenza vaccines; these are currently under development in laboratories worldwide. If such vaccines are immunogenic, efficacious, and able to confer long-lasting immunity, they might be integrated with or supplant traditional influenza vaccines.

KEYWORDS:

• Chimeric HA protein
• HA head-based approaches
• influenza virus
• stem-directed antibodies
• universal vaccines

Article Highlights

• The limits of available immunization tools and the future prospects and potentiality of universal influenza vaccines are discussed.

• Concerns raised about the risk of contamination and mutations in egg-grown influenza strains should be overcome by the new technologies.

• The need exists to better define correlates of protection against influenza, which potentially may vary according to individual characteristics, population, specific age-group, and vaccine type.

• The pros and cons of candidate vaccines based on the highly conserved epitopes of HA, NA, or the M2, NP, or M1 domains are presented.

• The lack of knowledge and validated methods of measuring alternative immune markers of protection against influenza remain substantial barriers to the development of more immunogenic, broadly cross-reactive, and effective influenza vaccines.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper is not funded.