Although the long-term goal is for homeless populations to achieve a 90% or higher HAV/HBV completion rates, strategies for successful outcomes emanate from the findings. These include targeting the groups least likely to complete the vaccine series with culturally competent and gender- and age-sensitive programs. These specific subgroups include the young and newly homeless persons and those who were least likely to seek substance use programs. Finally, considering accelerated time sequence HAV/HBV vaccine series may also