Researchers have developed a single-dose powdered vaccine that is inhaled directly into the lungs to produce an effective immune response. The vaccine can deliver multiple antigens, meaning one dose could provide broad-spectrum protection against several respiratory viruses.
The arrival of the COVID-19 pandemic has led to advances in vaccine technologies, including the now well-known mRNA vaccines. Most of these are administered by intramuscular injection, which produces a humoral – a body fluid, not cell-based – immunity and relies on antibodies to neutralize the virus. While intramuscular SARS-CoV-2 vaccines have been shown to reduce morbidity and mortality significantly, they have less impact on viral transmission rates.
Producing an immune response in the airway’s mucosal tissues is crucial for the early control of infection and can generate robust, long-term immunity with prompt recall responses. To address the problems associated with vaccines administered intramuscularly, researchers from the Institute of Process Engineering at the Chinese Academy of Sciences have developed a single-dose inhalable dry powder vaccine.
Their vaccine platform combines biodegradable microspheres with protein nanoparticles, the surface of which can display multiple antigens, the substances that cause the immune system to produce antibodies to them. Having more than one antigen expands the range of viral protection afforded by the vaccine and causes a more broad-spectrum immune response. For example, it could include antigens from different SARS-CoV-2 strains or SARS-CoV-2 and another respiratory virus vaccine.
Once the antigen nanoparticles are released, they can efficiently be taken up by the lungs. And, because the nanoparticles are sustained-release, they provide long-lasting humoral, cellular, and mucosal immunity with a single inhalation. The researchers tested their powdered vaccine in mice, hamsters and nonhuman primates, observing the strong production of antibodies and a local T cell (immune cell) response, indicative of effective viral protection.
“The components of this nano-micro system used natural proteins and approved polymer materials, and the effectiveness and safety of the vaccine have been systematically studied in non-human primates, indicating its great potential for clinical translation,” said Wei Wei, one of the study’s corresponding authors.
From a manufacturing point of view, being a dry powder means the vaccine doesn’t need to be refrigerated, significantly reducing storage and transportation costs and making it suitable for use in areas without or with limited refrigeration facilities.
The study was published in the journal Nature.
Source: Chinese Academy of Sciences
