Flu vaccine in a pill as effective as injectable form in human trials
Phase 2 human trial results have been published demonstrating the impressive efficacy of an oral form of the influenza vaccine. The trial compared the pill to the most commonly used injectable flu vaccine and found it as safe and effective as its counterpart.
Herd immunity is vital in slowing the spread of infectious diseases through a community. The more people that can be vaccinated, the better. However, one of the bigger scientific hurdles to overcome in getting more people vaccinated is the lack of many effective oral vaccinations.
The majority of current vaccinations are injection-based formulations. Tablet-based vaccines would be cheaper to manufacture and significantly easier to administer, but oral delivery methods have proved challenging to develop, primarily due to the harsh nature of the human gastrointestinal system.
Biotechnology company Vaxart has been working on an oral form of vaccination for several years. Its most recent milestone comes in an impressive Phase 2 trial demonstrating the efficacy of an oral influenza vaccine.
The randomized, double-blind and placebo-controlled trial recruited 179 healthy adults. All subjects received either a dose of the experimental oral vaccine, an injection of Fluzone (the most frequently used influenza vaccine), or a placebo. After around 90 days, all the subjects were then intranasally challenged with the influenza virus.
Alongside no serious adverse effects, the oral vaccine proved slightly more effective than the current market-leading injectable vaccine. The oral vaccine cohort, compared to placebo, demonstrated a 39 percent reduction in clinical disease signs and a 47 percent reduction in infection rates. These results were slightly better than the injectable vaccine cohort demonstrating only a 27-percent reduction in clinical disease, and 43-percent reduction in infection rates.
“These results provide clinical proof-of-concept for Vaxart’s proprietary technology being able to make an oral vaccine that is at least as protective as Sanofi’s Fluzone,” explains chief scientific officer of Vaxart, Sean Tucker. “The results of the clinical study also demonstrated that our oral tablet vaccine primarily protects through mucosal immunity, a potential key factor for improving influenza vaccine performance.”
Several more years of work are needed before the oral vaccine reaches the market and the current trial only tested a single strain of influenza. Most annual flu vaccines incorporate three or four of the most virulent strains circulating, so future studies will need to explore whether this oral administration works with trivalent or quadrivalent formulations.
Vaxart does suggest its oral platform should be effective in administering a variety of vaccines targeting pathogens that infect a host through mucosal membranes including the respiratory system. This means if the oral vaccine platform proves completely effective it could be incorporated into a variety of immunization strategies.
“A convenient and effective tablet vaccine may significantly increase current vaccination rates, generating important public health benefits for at-risk groups and the population as a whole,” says Wouter Latour, CEO of Vaxart. “These results also confirm the value of our oral vaccine platform, particularly for mucosal pathogens such as flu, norovirus, RSV, as well as coronaviruses such as SARS, MERS and the virus that recently emerged in China.”
The new study was published in the journal The Lancet Infectious Diseases.