In the ever-evolving world of swine influenza, staying ahead of the virus is a constant challenge for farmers, veterinarians, and public health officials alike. A recent study published in *Frontiers in Veterinary Science* sheds light on the effectiveness of current European swine influenza vaccines against contemporary Spanish strains, with implications that could reshape vaccination strategies and protect both animal and human health.
The research, led by Paloma Encinas from the Department of Biotechnology at the National Institute for Agricultural and Food Research and Technology (INIA-CSIC) in Madrid, Spain, delves into the cross-reactivity of antibodies induced by current vaccines. Using a murine model, the team tested the immune response generated by monovalent (MVV) and trivalent (TVV) vaccines against a range of Spanish swine influenza viruses (SIVs) isolated between 2016 and 2021, as well as human influenza A virus (IAV) strains.
The findings are striking. Sera from mice immunized with either MVV or TVV showed no hemagglutination inhibition (HI) antibodies against a 2019 Eurasian avian-like H1 (EAswH1) SIV. Moreover, the TVV did not induce cross-reactive HI antibodies against human seasonal H3 SIVs from the 2000s or the human seasonal H3 vaccine strain. “This lack of cross-reactivity is concerning,” Encinas notes, “as it suggests that current vaccines may not be providing adequate protection against some of the circulating strains.”
The study also revealed that geometric mean (GM) HI titers of sera from TVV-immunized mice were below the protection threshold against recent human seasonal-like H1 (HUswH1) SIV, EAswH1 SIV, and the human seasonal H1 vaccine strain (HuVacH1). However, HI antibodies induced by MVV showed high cross-reactivity with a 2019 EAswH1 SIV isolate, indicating that certain vaccine formulations may offer better protection against specific strains.
The commercial impacts for the agriculture sector are significant. Swine influenza outbreaks can lead to substantial economic losses due to reduced growth rates, decreased feed efficiency, and increased mortality. Effective vaccination is crucial for controlling the severity of the disease and minimizing these losses. The findings suggest that current vaccines may not be fully effective against some contemporary SIVs circulating in Spain, highlighting the need for updated vaccine strains that better match emerging viruses.
“This research underscores the importance of continuous surveillance and the development of new vaccines to keep pace with the genetic diversity of swine influenza viruses,” Encinas explains. “By doing so, we can better protect both animal health and public health, as swine influenza has the potential to spill over into humans.”
The study’s implications extend beyond Spain, as similar trends in antigenic variability and vaccine effectiveness may be observed in other regions. The findings call for a global effort to monitor swine influenza strains and develop more effective vaccines. As the agricultural sector faces increasing pressures from climate change, globalization, and emerging diseases, investing in advanced vaccination strategies becomes ever more critical.
In the words of Encinas, “The future of swine influenza control lies in our ability to adapt and innovate. By staying ahead of the virus, we can safeguard the health of our animals, the livelihoods of farmers, and the safety of our communities.”