Pharma-Pen, Inc. (hereinafter "Pharma-Pen") and Virginia Commonwealth University ("VCU") have partnered to demonstrate the safety, effectiveness and tolerability of two versions of the Pharma-Pen(TM) auto-injector for IM injection (Treatment 1) or SC injection (Treatment 2) by untrained users compared to standard IM injection (Treatment 3) by a licensed healthcare professional (e.g. nurse). Commercially available Influenza vaccine will be used as a model to demonstrate the ease-of-use and effectiveness of the delivery system. The proposed study will compare safety and immunogenicity of three treatments in healthy volunteers: 1) Self-administered flu vaccine given IM by auto-injector in the thigh; 2) Self-administered flu vaccine given subcutaneously by auto-injector in the thigh; 3) Standard IM vaccine administered in the deltoid muscle by a licensed clinician. Primary objectives of this program are to demonstrate that the Pharma-Pen(TM) system can be safely and successfully used by untrained adults to self-inject with vaccines and to show that the resulting immunogenicity is comparable to vaccinations administered by trained medical personnel using conventional syringe/needle technology. There will be secondary information that accrues from the study. The outcomes of the IM route can be compared to the outcomes of the SC route, and the outcomes of the IM route in the deltoid muscle can be compared to the outcomes in the lateral thigh muscle. This safety/proof-of-concept study will be a randomized, single-dose, open-label, parallel, three treatment trial in 120 healthy subjects (male & female, ages 18 to 50 years) who have not received an influenza vaccine for at least four years, meet all inclusion/exclusion criteria, and sign an informed consent form. The individuals should be non-medical individuals with no experience in giving IM or SC injections. Each subject will be randomly assigned to one of three treatments. The study is divided into two successive parts (1A and 1B). Part 1A will be conducted in the first 12 subjects who will be randomized to only Treatment 1 (3 males, 3 females) and Treatment 2 (3 males, 3 females). The purpose of part 1A is to obtain initial safety information on the IM and SC auto-injectors (Pharma-Pen[TM]) in a few carefully observed subjects (10% of total) to assure that the devices are functioning as designed and do not produce significant injury to the injection site. Part 1A will be conducted under the direct supervision of the Medical Investigator (MI). The results of part 1A will be forwarded to the appointed Safety Monitoring Committee (SMC). If serious device deficiencies are detected early in part 1A, the study may be terminated prior to all 12 subjects completing this initial phase. Part 1B will be initiated only after approval of the MI and SMC, based upon the data from the 12 subjects in part 1A. Part 1B will involve the remaining 108 subjects. All injections will be performed under licensed clinician supervision.