The purpose of this study is to determine if the administration of flu vaccine using Needle-Free is equivalent to Needle and Syringe administration as measured by laboratory tests of immune response.

Primary:

To evaluate the non-inferiority of flu vaccine administered by needle-free intramuscular (IM) injection versus needle and syringe IM injection as determined with serum hemagglutination inhibition (HAI) reciprocal titers in healthy adults between 18-64 years.

Secondary:

To compare tolerability and safety of the vaccine in the same population based on specifically solicited local and systemic reactions occurring through 7 days post-immunization and adverse events spontaneously reported through approximately 28 days post immunization.

Inclusion Criteria:

• Adults aged ≥ 18 and ≤ 64 years of age at time of enrollment
• Willing and able to give informed consent after reading the consent form and given adequate opportunity to discuss the study with the investigator or qualified designee
• Willing and able to adhere to all protocol required study procedures and to attend scheduled visits
• Able to receive the trivalent influenza vaccine (TIV) or quadrivalent influenza vaccine (QIV) based on PI judgment
• Stable health status with no exclusionary medical or neuropsychiatric conditions as determined during the screening evaluation and based on the clinical judgment of the investigator or qualified designee
• Access to a consistent means of telephone contact

Exclusion Criteria:

• Presence of any febrile illness (oral temperature >38 °C) on the day of immunization. Such subjects will be reevaluated for enrollment after resolution of illness
• Presence of significant acute or chronic uncontrolled medical or neuropsychiatric illness and /or presence of any significant condition that may prohibit inclusion as determined by the investigator or his qualified designee. Uncontrolled is defined as: requiring institution of a new treatment within 1 month prior to study enrollment or change in medication dosage in the month prior to study enrollment
• Any known immunosuppressive condition including: history of human immunodeficiency virus (HIV) infection, cancer or cancer treatment within 3 years of study enrollment, systemic glucocorticoids (in a dose ≥10 mg prednisone daily or equivalent for more than 7 consecutive days or for 10 or more days in total) within 1 month of study enrollment, or any other cytotoxic or immunosuppressive drug within 3 months of study enrollment. Any significant disorder of coagulation that would increase the risk of intramuscular injections or treatment with Coumadin derivatives or heparin
• Known or suspected to be allergic to eggs, chicken protein, neomycin, polymyxin or influenza vaccine
• History of severe or previous serious adverse reaction after an influenza vaccination
• Receipt of any immunoglobulin and/or blood products within 3 months of immunization or planned administration of any of these products during the study period
• Prior history of any demyelinating disease including Guillain-Barre syndrome.
• Presence of an active neurological disorder
• History of significant alcohol or drug abuse within one year prior to study enrollment
• Influenza vaccination or laboratory confirmed influenza infection within the previous six months before study vaccination or planned influenza vaccination during the study period
• Planned administration of any non-influenza vaccines 30 days prior to the study or during the study period
• Pregnant or plans to become pregnant during the study period
• Currently enrolled in another vaccine or drug study

Adverse events are reported based on participant recall of events over 28 days

Spontaneously reported adverse events