Background
Immunization is considered one of the most cost effective public health interventions for reducing child morbidity, mortality and disability. The aim of this work is to describe the application of the Bottleneck analysis (BNA) process to assess gaps in immunization services in Ghana and implications for sustaining the gains in Immunization coverage.

Methods
A national assessment was conducted in May 2015, through use of desk reviews, field visits and key informant interviews. Quantitative data were analysed with the BNA Tool (an excel-based tool) based directly on service coverage data and programme monitoring and review reports in Ghana. Outputs were generated based on service coverage indicators; supply side/health system factors (commodities, human resource and access), demand side (service utilisation) and quality/effective coverage. National targets were used as benchmarks to assess gaps in coverage indicators.

Results
In all, only 50% of regions and districts had health facilities with at least 80% of health care workers training provided in-service training on routine immunization; only 40% of district had communities with functional fixed or outreach EPI service delivery point and over 70% of regions and districts had challenges with effective coverage of infants aged 0-11 months fully immunized during the past year.

Other key health system bottlenecks included, limited number of fixed and outreach sites, difficult to reach island communities along the Volta Basin, inadequate storage facilities for vaccines at lower levels, stock out of vaccines and auto destruct syringes and absence of updated policies/field guides at services delivery points/facilities. In addition, inadequate in-service training in routine Immunization and absence of good quality data were major challenges. Demand side bottlenecks included fear of mothers on the safety of multiple vaccines and limited active involvement of communities in Immunization service delivery.

Conclusion
The BNA tool and approach provided data driven planning of health service in Ghana. This resulted in the development of regional and national operational plans for immunization and will be the baseline for evaluating the national programme in three years.