While the COVID-19 vaccines continue to dominate headlines, another vaccine that has been on the consumer market since the end of World War II may be soon getting a redesign.
Scientists from UW Medicine and the National Institutes of Health (NIH) have created a new experimental influenza vaccine that could be the next breakthrough in advancing vaccine technologies.
“We have annual flu vaccines because the virus mutates every year,” Neil King, a researcher at the Institute for Protein Design at UW Medicine, said in a press release. “The problem we were trying to address in this work is really just making flu vaccines better.”
The vaccine that is currently available in the United States is made with four weakened or inactivated influenza virus strains. Prior to a flu season each year, World Health Organization scientists predict which four strains will be most prevalent and recommend specific virus strains to be put in vaccines.
This means that the effectiveness of the current vaccine is tied to how well scientists can predict which viruses will circulate during the coming flu season.
“If those predictions are good, the vaccine’s effectiveness is very formidable,” Daniel Ellis, lead author of the study, said. “But when those predictions do not go as well, the effectiveness drops sharply.”
The new vaccine, instead of using weakened or inactivated virus strains, employs custom-made protein nanoparticles that have the antigen hemagglutinin (HA) from four different influenza viruses attached to them.
The nanoparticle platform was chosen as the base for the vaccine because of its shape and how it repetitively arrays antigens, similar to other viruses, which the immune system has evolved to recognize as a danger signal.
“With the current vaccine, the immune system targets only parts of the HA molecules that often mutate,” Ellis said. “[The experimental vaccine] takes the same HA proteins that are in [the] virus but tries to put them in a different way that is more attractive to the immune system so that it can see parts of the HA that, normally, it is not able to recognize.”
In trials with mice, ferrets, and nonhuman primates, the vaccine elicited neutralizing antibody responses that were equivalent or superior to the currently available vaccines.
Furthermore, the nanoparticle vaccine prompted protective antibody responses to influenza viruses that were not contained in the vaccine formulation, which is not seen with commercial vaccines.
“The responses that we got were so broad that it did not only cover things that could represent bad predictions during a flu season — it also was capable [of] recognizing influenza viruses that are very different, including avian viruses,” Ellis said.
As for the future of this nanoparticle vaccine, there are still several more steps ahead before it reaches the consumer market. The vaccine is currently in the manufacturing stage for more trials and is scheduled to enter a Phase 1 clinical trial next month at the NIH, where it will be tested on people for the first time.
Reach reporter Timothy Phung at firstname.lastname@example.org. Twitter: @TimPhung
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