Dr Bruce Weniger, CAPT, US Public Health Service (ret.), International Professor, Research Institute for Health Sciences, Chiang Mai University delivered a presentation last week at the World Vaccine Congress showing his latest research on promising needle-free technologies for alternative vaccine delivery.
There have been numerous advances in needle-free vaccine delivery systems. Dr. Weniger summarized a number of specific examples in use and under development. They range from jet injections to cutaneous, intranasal, pulmonary inhalation and oral ingestion methods. Non-sterile re-use of injection needles is a troubling cause of damaging infectious disease transmission in the US and around the world. Needle-free technologies can eliminate infections from needle re-use, as well as improve the capacity for mass vaccinations in the case of outbreak prevention and management. In April 1947, after the appearance of 12 smallpox cases and 2 deaths in New York, more than 5.265 million people were vaccinated in two weeks thanks to a health care workforce numbering in the thousands. Dr. Weniger asked whether this was a feasible accomplishment in modern times, and then discussed the history of vaccination method advancements. In the 1950′s, the Salk polio (POLIPV) mass vaccination campaigns utilized a high-speed multi-use nozzle jet.
In 1976, approximately 43 million doses of flu vaccinations were administered to protect against Swine flu. Currently, there are a variety of new platforms for vaccination without needles, though a barrier to understanding and comparing these technologies involves what Dr. Weniger called the terminological "tower of babel" in the medical literature. Often, various terms such as "dermal", "cutaneous", "epithelial", "topical", etc. are used to describe what are essentially highly similar skin application methods. He encouraged standard nomenclature to promote consistency in the industry. Different companies may use slightly different methods to deliver the vaccine beyond the skin, including sand-paper type friction, patches, hollow microneedles, dissolvable microneedles, etc.
The WHO has sponsored two trials exploring the use of cutaneous vaccination as a potential strategy for polio eradication, conducted in Oman and published in the New England Journal of Medicine, as well as in Cuba and published in the Journal of Infectious Diseases. The PharmaJet intradermal Tropis Jet Injector is being explored as a method for cutaneous vaccination for future approved Dengue vaccines. As for intranasal sprays, there is BD’s accuspray nasal spray system and the Optinose Nasal Delivery Device. For pulmonary inhalation of aerosols, Sabin pioneered this method but there are concerns about cross contamination between patients. From the Grand Challenges in Global Health (#3), dry powder measles vaccine inhalers are being developed. Two examples to watch are Aktiv-Dry LLC in Colorado and their PuffHaler as well as BD’s Solovent.
Dr. Weniger continued by discussing oral ingestion vaccines and by asking what the ideal administration methods might be for different immunization purposes.
Check back here in a couple of days for the presentation. Excellent presentation Dr Bruce!