Many Americans have good access to health care that enables them to benefit fully from the Nation's health care system. However, others face barriers that make the acquisition of basic health services difficult. As demonstrated by extensive research and confirmed in the 2003 and 2004 National Healthcare Disparities Reports, racial and ethnic minorities and persons of low SES are disproportionately represented among those with access problems. Poor access to health care comes at both a personal and societal cost: for example, if persons do not receive vaccinations they may become ill and spread disease to others, increasing the burden of disease for society overall, in addition to the burden borne individually.