ATLANTA—In the event of a large-scale influenza pandemic, widespread vaccination will be key to public health, but the distribution and maintenance of serum stocks for injection can be problematic. Taking advantage of the fact that most pathogens enter the body through skin or mucosal tissues, researchers at the CDC and Altea Therapeutics designed a needle-free transdermal patch delivery system called the PassPort System.
As they described in Clinical and Vaccine Immunology, the researchers examined the efficacy of the patch to vaccinate mice with recombinant influenza antigen (alone or with one of two adjuvants) compared to standard injection. Collecting sera from mice after two booster immunizations, the scientists noted that the patch produced a significant virus-specific hemagglutination-inhibition (HI) response and that the use of CpG oligonucleotide adjuvant produced HI titers comparable to immunization by injection.
The researchers then looked for signs of protective immunity by challenging the mice with 10X or 50X LD50 of an H5N1 virus, looking for changes in body weight and/or death. They found that mice receiving antigen in CpG adjuvant lost little or no weight and survived infection while the negative control mice lost more than 20% body weight and succumbed to infection.