Tiny Nanoparticles Contribute Greatly to the Development of Universal Flu Vaccine

Imagine being vaccinated against influenza with a single visit to your doctor. She simply gives you a “magic shot” and then tells you that you won’t see her again, at least not for flu, for the rest of your life. Sound like a Disney movie? Don’t tell Dr. Masaru Kanekiyo that. He is a staff scientist working at Vaccine Research Center, National Institutes of Health, and he has more than imagined it, he has been developing such so-called universal flu vaccines with colleagues for years.

Capable of constantly mutating in the hemagglutinin (HA) surface protein, influenza viruses get around the current commercial flu vaccines and caused an estimated 12,000-61,000 influenza-related deaths in the US annually. 

Source: CDC, “Materials developed by CDC” 

Therefore, Masaru and his colleagues garnered the lion's share of the attention when their work was recently published in Nature, reporting an experimental vaccine that could prompt a vigorous, long-lasting antibody response against a broad range of influenza virus strains.

Nanoparticle Flu Vaccine Design

To design such a “magic” vaccine, 20 HA proteins from four seasonal flu virus strains during 2017-18 season were fused to a nanoparticle-based immunogen and co-displayed there in a repeating pattern, being expected to send a stronger “warning” signal to the immune system than that of the conventionally designed vaccines and thus elicit more robust antibody responses.

Computer-generated image of nanoparticle influenza vaccine.

(NIAID)

Vaccine Efficacy in Experimental Animals

The newly developed nanoparticle flu vaccine was tested in mice, ferrets and non-human primate models. Comparing to the control groups receiving standard flu vaccine, a commercial 2017–2018 quadrivalent influenza vaccine containing the same four human flu virus strains, nanoparticle flu vaccinated animals showed the same or stronger antibody responses against the vaccine HA proteins.

Next, the investigators analyzed plasma from ferrets or mice vaccinated by conventional flu vaccines and nanoparticle-based vaccines for protection against historical viruses such as H1N1, H3N2, H5N1 and H7N9. The results showed that the mosaic nanoparticle vaccines offered high (as high as 92%) protection against those viruses whereas standard flu vaccines only provided negligible protection (10% or 12%). The broad protection range suggested that those nanoparticle vaccines might be able to provide consistent year-to-year protection against seasonal influenza viruses.

Clinical Trail of the Vaccine

NIH announced on June 1 that a first-in-human, Phase 1 clinical trial has been launched to assess the safety and immunogenicity of this universal influenza vaccine candidate.  Once the vaccine is proved safe and effective, we can expect a nanoparticle-based vaccination that offers us a long-lasting protection against multiple flu virus strains through merely one single shot.

Reference

Boyoglu-Barnum, Seyhan, et al. "Quadrivalent influenza nanoparticle vaccines induce broad protection." Nature 592.7855 (2021): 623-628.