The Inactivated Polio Vaccine (IPV) study, which uses US-based Bioject Medical Technologies' Biojector2000, is intended to demonstrate whether three fractional doses of IPV given intradermally are as effective as a full dose given intramuscularly. The move to evaluate the feasibility of replacing traditional needle and syringe immunizations comes at a time when the World Health Organization (WHO) is working towards improving the safety of immunizations in general and reducing needle-stick injuries. The Biojector2000, which was introduced in 1993, is paving the way in needle-free devices as a safer system with the potential for dose sparing vaccines. With around 12 billion needle injections every year for the delivery of vaccines and protein therapeutics such as insulin, growth hormones and erythropoietin, the rapidly expanding needle-free injection market, set to hit $3bn by 2010. "The Biojector2000 injection system is already being used to improve the safety of immunizations in numerous health centers, and WHO considers that this and other needle-free injection systems being developed by Bioject could greatly contribute to improving the safety and ease of immunizations worldwide," Dr Martin Friede of WHO said in a statement. The system works by forcing liquid medication at a high speed through a tiny orifice held against the skin. This creates a fine stream of high-pressure fluid penetrating the skin and depositing medication in the tissue beneath. Approved by the US Food and Drug Administration (FDA) for delivering subcutaneous and intramuscular injections, each device is able to deliver over 100,000 injections and is powered by a carbon dioxide cartridge. The plastic syringe compartment, discarded after each use, does not need to be discarded in a sharps container due to being needle-free, thereby reducing hazardous waste. The Oman study will be performed on 400 newborns over a seven-month period. Dr Roland Sutter of WHO said: "Intradermal delivery of reduced doses of IPV could help countries with limited resources to use this vaccine. Intradermal delivery is difficult to perform reliably with needles and syringes, and we feel that needle-free delivery systems such as the Biojector2000 would be a safer, easier and more reliable method for intradermal delivery of IPV." Bioject executive vice president and chief medical officer Dr Richard Stout said he was pleased the system had been chosen for the study. "We are very encouraged with results from other intradermal studies and see this as a possible delivery route for current, as well as future, vaccines. Bioject is also involved in other studies in Latin America in collaboration with the Centers for Disease Control and WHO, which are evaluating the dose sparing possibility with other vaccines," he said. Other needle-free liquid injections include Ped-O-Jet, Iject, Medi-jector and Intraject and for powder injections PMED, formerly known as Powderject. Earlier this year, a team of researchers based at the University of California in collaboration with drug delivery company StratGent Life Sciences, developed a novel needle-free system which minimizes the depth of drug penetration by using pulsed micro-jets at very high speeds and very small volumes. Biojector2000 has shown promising results in a study involving the anti-HIV drug T-20 (enfuvirtide) currently marketed by Roche as Fuzeon. In another study for the treatment, patients have said they preferred the Biojector2000 system more than the needle and syringe.