Animal tests suggest new approach safer than nasal flu vaccination

Study cited by PNAS journal as distinguished article

                                      
Dr. Kweon Mi-na,                                                                IVI Researcher Song Joo-Hye C
Chief of the IVI’s mucosal immunology section 

The IVI has found a way to administer vaccines sublingually, which doesn’t require needles. In two recent studies, IVI scientists and their collaborators have shown that vaccines administered under the tongue (but not swallowed like oral vaccines) can elicit a broad range of immune responses in various mucosal tissues, including the respiratory, digestive, and reproductive tracts, which are major means by which microbial pathogens enter the body.

 Researcher Song Joo-Hye and her colleagues at the IVI have found that an experimental flu vaccine administered sublingually was highly effective in protecting mice from influenza virus infection. When the flu vaccine was applied under the tongue, animals developed strong immune responses in their lungs and were fully protected from the disease when later exposed to a severe form of influenza virus, which is normally fatal to mice.

Dr. Kweon Mi-na, chief of the IVI’s mucosal immunology laboratory who oversaw the study, said, "This study also suggested that this method of vaccine administration poses no risk of the vaccine being redirected to the central nervous system, which is a potential risk of administering influenza vaccines intranasally." The study is published in the prestigious Proceedings of the National Academy of Sciences in the United States (online early edition was issued on January 28).
 

Liquid formulation of a sublingual vaccine  Gel formulation of a sublingual vaccine

This study builds on an earlier IVI study, conducted in collaboration with INSERM (National Institute for Health and Medical Research) in France and Gothenburg University in Sweden. In addition to offering a convenient and safe way to deliver vaccines without needles, scientists in that study found that the sublingual route helps overcome the two main drawbacks of orally administered vaccines: destruction of antigens as they go through the gastrointestinal tract (e.g., from stomach acids), and failure to induce strong immune responses in the respiratory tract. This first study appeared in the December 2007 issue of Vaccine.

 “These studies provide a basis for further human testing of this alternative form of needle-free vaccination. Aside from its convenience, sublingual vaccination appears to spread immunity to a broader range of organs than the classical routes of injecting or ingesting vaccines,” said Dr. Cecil Czerkinsky, IVI Deputy Director-General for Laboratory Science. “If these findings are replicated in humans, they could pave the way for the development of a new generation of vaccines that could be used for mass vaccination against respiratory infections, including avian influenza viruses that may cause pandemics in humans.”

Dr. John Clemens, IVI Director-General who is a world authority on vaccine evaluation, said, “These studies are important milestones for the IVI. Sublingual vaccination is an entirely new approach to the delivery of vaccines. This approach offers the possibility of vaccinating against a variety of infections without the risks posed by delivering vaccines with needles.”