Universal, or cross-protective, vaccines—so named for their effectiveness against several flu strains—are being developed in various labs worldwide and some are already in clinical trials.
As reported in the Proceedings of the National Academy of Sciences, the new vaccines would make a bout with influenza less severe, making it more difficult for the virus to spread. At the same time, the vaccines could target relatively unchanging parts of the virus and hamper its ability to evolve and evade immunity.
A computational model shows these factors could achieve unprecedented control of the flu virus both seasonally and during outbreaks of highly contagious new strains. Cross-protective vaccines could even improve the effectiveness of current vaccines, which are designed to only fight specific flu strains, the researchers report.
Controlling the flu, which is now like “chasing a moving target,” could advance from the current reaction stage to that of real population-wide prevention, says lead author Nimalan Arinaminpathy, a postdoctoral research associate who works in the lab of co-author Bryan Grenfell, professor of ecology and evolutionary biology at Princeton University.
“Because the flu quickly evolves to escape host immunity, current vaccines tend to be prioritized for inoculating specific high-risk groups such as asthma sufferers and the elderly every year,” Arinaminpathy says.
“So, at the moment, vaccine programs focus on clinical protection for those receiving the vaccine, but we hope to eventually graduate to being able to control the virus’ spread and even its evolution. Our model provides a strong conceptual basis as to how and why the universal vaccines would achieve that.”
The research presents a realistic and important assessment of how the universal vaccines’ ability to work against a breadth of flu strains can be wielded to benefit public health, says James Lloyd-Smith, assistant professor of ecology and evolutionary biology at the University of California-Los Angeles. Lloyd-Smith had no role in the study, but is familiar with it.
“This is the first study that looks at the population consequences of the next generation of vaccines, both in terms of epidemiological impact and evolutionary impact on the virus,” Lloyd-Smith says. “They combined the latest information out of these vaccine trials, and the very latest and best models of influenza virus evolution and epidemiology. They put those together and asked important and relevant questions about how this new vaccine would actually play out.
Futurity & Proceedings of the National Academy of Sciences