Dose Sparing Intradermal S-OIV H1N1 Influenza Vaccination Device

Inclusion Criteria: * All participants qualified for the HA/ CHP Mass Vaccination Program for S-OIV H1N1 as stated above: including all elderly at the age of 65 or above and all adult patients at the age of 21 or above with chronic illness including hypertension, diabetes mellitus, ischemic heart disease, cerebrovascular disease, thyroid disease and chronic renal failure. * All patients give written informed consent. * Subjects must be available to complete the study and comply with study procedures. * Willingness to allow for serum samples to be stored beyond the study period, for potential additional future testing to better characterize immune response. Exclusion Criteria: * Clinically significant immune-related diseases, significant recent co-morbidities and pregnant volunteers. * Inability to comprehend and to follow all required study procedures. * History or any illness that might interfere with the results of the study or pose additional risk to the subjects due to participation in the study * Have received an S-OIV H1N1 vaccination. * Have a recent (starting May 2009) history (documented, confirmed or suspected) of a flu-like disease). * Have a known allergy to eggs or other components of the Study Vaccines (including gelatin, formaldehyde, octoxinol, thimerosal, and chicken protein), or history of any anaphylaxis, serious vaccine reactions, to any excipients. * Have a positive urine or serum pregnancy test within 24 hours prior to vaccination, or women who are breastfeeding. * Female of childbearing potential, not using any acceptable contraceptive methods for at least 2 months prior to study entry or that do not plan to use acceptable birth control.