AAHI Advances its Spray Dried Vaccine Platform

FEBRUARY 2024

AAHI recently launched its innovative spray dried vaccine platform to develop dry powder vaccine formulations that can be inhaled.  The ability to provide traditional (subunit protein) and RNA vaccines in an aerosolized, inhalable dry powder form will increase affordability, ease of use, and effectiveness of vaccines against respiratory infectious diseases.  

Highly contagious respiratory diseases such as tuberculosis, influenza, and COVID-19 remain the world’s leading infectious killers. Respiratory viruses like RSV and seasonal influenza cause increasingly greater numbers of hospitalizations year over year, overburdening our healthcare system.  Currently available vaccine technology can’t keep up, especially in low-resource, remote, and rural areas of the world, such as developing nations.  

The COVID-19 vaccine roll-out highlighted global health inequities, as vaccines were largely manufactured and first distributed in high income countries, and the significant obstacles to low-and middle-income countries’ access to effective vaccines, including cold chain requirements for storage and transport, last-mile delivery, and shortages of trained medical personnel to administer vaccines. Two years after the onset of the COVID-19 pandemic, 79% of high-income countries were fully vaccinated, compared to 15% of low-income countries.1 These are the facts that motivated AAHI scientists to double down on their commitment to develop platforms for vaccines that can realistically be made available to underserved populations, to bridge such accessibility gaps and reduce the burden of disease worldwide.

Our formulations team, led by Christopher Fox, PhD, Senior Vice President of Formulations, is growing, acquiring more expertise in dry powder technology to expand a different approach to developing equitably accessible vaccines against respiratory infection.  

We are focused on three priorities:

1. Prevent transmission of highly infectious respiratory diseases

A DIFFERENT ROUTE OF DELIVERY

Nasal (up the nose) or pulmonary (inhalable) vaccine delivery may work better than vaccines injected in the arm because it can trigger a mucosal immune responses at the gates of entry into the body.

AAHI demonstrated immunogenicity and efficacy of it's spray dried vaccine platform in preclinical models, comparing lung inflammation reduction of various presentations of its tuberculosis vaccine candidate, ID93+GLA-SE. 

There is evidence that inhalable vaccines provide more robust protection against respiratory disease. CanSino Biologics in China rolled out the first commercially inhalable vaccine against COVID-19, Convidecia Air, and demonstrated that the vaccine induced strong humoral, cellular, and mucosal immunity – a robust response against the virus. The vaccine is inhaled by mouth from a nebulizer.

2. Lower supply chain costs and ease vaccine distribution to communities with limited healthcare infrastructure

ELIMINATE THE COLD CHAIN

Removing water from vaccine formulations makes the product stable in ambient and extreme temperatures than traditional liquid vaccines that require highly monitored refrigeration and ultra-cold freezing to transport, store, and distribute. 

AAHI demonstrated that it's spray dried presentation of its ID93+GLA-SE tuberculosis vaccine candidate is stable for at least two months at 25°C (77°F). 

Last-mile immunization cold chain delivery can easily result in accidental freezing and/or warming of vaccines due to lack of temperature monitoring and adequate infrastructure, resulting in spoiled vaccine that are no longer effective and go to waste. One study in 2019 demonstrated that 25% of vaccines degrade before they get to the health centers that administer them.2 That was before RNA technology shifted the cold chain paradigm to an extreme freezing temperature, a more challenging process to maintain. Temperature deviations during vaccine transport procedures result in an estimated loss of $34.1 billion every year.2

SIMPLIFY MANUFACTURING PROCESSES

Spray dried vaccine manufacturing is a continuous process that enables high-volume, rapid production at commercial scale, in the face of emerging infectious health threats. 

AAHI successfully manufactured lab-scale vaccine candidates of its ID93+GLA-SE subunit tuberculosis vaccine candidate and its pandemic influenza saRNA-NLC vaccine candidate using a newly acquired spray drier.  

Freeze-dried (lyophilized) vaccines is a different dried presentation that is commercially available, the most successful of which is MenAfriVac® - a meningitis A vaccine that is stable in temperatures up to 40°C for four days. The immunization campaign in Benin alone, a country in West Africa, resulted in 1.5 million people vaccinated within 10 days. MenAfriVac® has nearly eliminated meningitis A in 26 countries in Africa.3

But AAHI scientists identified basic barriers to freeze-dried vaccine that are mitigated by the spray dry vaccine technology – batch manufacturing processes that are difficult to scale and the need for sterile water to reconstitute the vaccine into its liquid form at bedside.

3. Increase vaccine uptake and make them easier to administer

NEEDLE-FREE ADMINISTRATION

Eliminating the needle allows for self-administration of vaccines so that trained medical professionals, of which there is a global shortage, are no longer needed and the fear of needles is mitigated, encouraging greater vaccine uptake. 

AAHI scientists evaluate different delivery devices for optimal vaccine dispersion in the nose and the lungs to provide efficient coverage and protection upon administration. 

AAHI continues to acquire expertise in aerosolized dry powder vaccine development, advance in-house spray dray vaccine manufacturing capabilities, and foster collaborations with partners to bring the spray dried vaccine platform into human clinical trials. 

1. Lazarus, Jeffrey V et al. “COVID-19 vaccine wastage in the midst of vaccine inequity: causes, types and practical steps.” BMJ global health vol. 7,4 (2022): e009010. doi:10.1136/bmjgh-2022-009010

2. Nagurney, Anna. "The Challenges of Vaccine Cold-Chain Distribution Must Be Met to End the Pandemic" Global Biodefense, October 5 2020. 

3. Science Chronicle. "MenAfriVac: first use of vaccine outside of the cold chain in Africa" Journos Diary, January 16, 2016.