The study conducted in Sierra Leone demonstrates the effectiveness of last-mile delivery of COVID-19 vaccines to remote, rural communities. By using mobile vaccination teams and health professionals, along with community mobilization, the intervention increased the immunization rate by about 26 percentage points within 48–72 hours. The number of vaccinations administered more than doubled, with an average of 55 people vaccinated per site. The intervention cost approximately $33 per person vaccinated, with transportation being the largest expense. The study highlights the importance of addressing access issues to improve vaccination rates, particularly in low-income countries. It also suggests that bundling multiple health interventions can further reduce costs. The findings have broader implications for global public health, emphasizing the need to prioritize access interventions to increase vaccine equity and coverage.The study conducted in Sierra Leone demonstrates the effectiveness of last-mile delivery of COVID-19 vaccines to remote, rural communities. By using mobile vaccination teams and health professionals, along with community mobilization, the intervention increased the immunization rate by about 26 percentage points within 48–72 hours. The number of vaccinations administered more than doubled, with an average of 55 people vaccinated per site. The intervention cost approximately $33 per person vaccinated, with transportation being the largest expense. The study highlights the importance of addressing access issues to improve vaccination rates, particularly in low-income countries. It also suggests that bundling multiple health interventions can further reduce costs. The findings have broader implications for global public health, emphasizing the need to prioritize access interventions to increase vaccine equity and coverage.