Participation in flu immunization projects: what can we expect in the future?
D000328:Adult; D001294:Attitude to Health; D004522:Educational Status; D005260:Female; D006801:Humans; D007114:Immunization; D007182:Income; D009980:Influenza A virus; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D010342:Patient Acceptance of Health Care; D010414:Pennsylvania; D012737:Sex Factors