Swine influenza A virus: challenges and novel vaccine strategies

Abstract

Swine Influenza A Virus (IAV-S) imposes a significant impact on the pork industry and has been deemed a significant threat to global public health due to its zoonotic potential. The most effective method of preventing IAV-S is vaccination. While there are tremendous efforts to control and prevent IAV-S in vulnerable swine populations, there are considerable challenges in developing a broadly protective vaccine against IAV-S. These challenges include the consistent diversification of IAV-S, increasing the strength and breadth of adaptive immune responses elicited by vaccination, interfering maternal antibody responses, and the induction of vaccine-associated enhanced respiratory disease after vaccination. Current vaccination strategies are often not updated frequently enough to address the continuously evolving nature of IAV-S, fail to induce broadly cross-reactive responses, are susceptible to interference, may enhance respiratory disease, and can be expensive to produce. Here, we review the challenges and current status of universal IAV-S vaccine research. We also detail the current standard of licensed vaccines and their limitations in the field. Finally, we review recently described novel vaccines and vaccine platforms that may improve upon current methods of IAV-S control.

Keywords: DNA; computationally designed vaccines; inactivated virus; live attenuated virus; nanovaccine; replicon particle; swine influenza A virus; vectored.

Figure 1

Temporal patterns of H1 IAV-S in worldwide swine populations from 1930-2022. All unique swine H1 IAV-S strains were downloaded from the Bacterial and Viral Bioinformatics Resource Center (Bacterial and Viral Bioinformatics Resource Center | BV-BRC (accessed on 14 October 2023)) and classified into H1 U.S. and global phylogenetic clades. Temporal patterns of diversity are visualized by year and the proportion of each designated clade was calculated based on total number of accessions submitted for a given year. Total number of accessions submitted per year/timeframe are indicated above each bar. Cross-species transmission events (human-to-swine or avian-to-swine) are indicated with arrows and the respective clade deposition.

Figure 2

Temporal patterns of H3 IAV-S in worldwide swine populations from 1977-2022. All unique swine H3 IAV-S strains were downloaded from the Bacterial and Viral Bioinformatics Resource Center (Bacterial and Viral Bioinformatics Resource Center | BV-BRC (accessed on 16 October 2023)) and classified into H3 U.S. and global phylogenetic clades. Temporal patterns of diversity are visualized by year and the proportion of each designated clade was calculated based on total number of accessions submitted for a given year. Total number of accessions submitted per year/timeframe are indicated above each bar. Cross-species transmission events (human-to-swine) are indicated with arrows and the respective clade deposition.

Figure 3

Novel experimental vaccine platforms against IAV-S. Vaccine type, platform, induction of humoral and cell-mediated immunity, inhibition by MDA, induction of VAERD, and protection against challenge are summarized for each novel vaccine platform.