Scaling up coverage of immunisation in the poorest countries will require substantial investments in the health systems that deliver vaccines. Constraints that affect immunisation delivery often affect other essential health interventions. By keeping IFFIm resources flexible, eligible countries will be able to use them to alleviate these system-wide barriers and potentially lead to a step change in the provision of health services.

Funds are expected to be allocated based on need and absorptive capacity. Countries with lower immunisation rates, high numbers of unvaccinated children, and large internal disparities (i.e., between states) will be given more resources. Smaller investments will be made in better performing countries, recognizing that lower-income countries still need additional resources to maintain achievements and further improve the quality of immunisation services.

• Measles and neonatal tetanus campaigns
  To drive mortality down quickly from highly infectious, vaccine-preventable diseases such as measles and tetanus, supplemental immunisation activities, often referred to as "immunisation campaigns", will be funded in the countries where the need is greatest. Such mass campaigns will be designed and executed with the additional goal of strengthening routine health and immunisation services. By strengthening immunisation services, the gains made through these campaigns will be maintained and strengthened in the future.
• Polio vaccine stockpile
  Once the world is declared to be polio-free, a stockpile of polio vaccine will be required to protect against any future recurrence. This vaccine must be produced very quickly in the narrow window of opportunity between the interruption of transmission and OPV cessation. This OPV (oral polio vaccine) stockpile will serve as an "insurance policy" in the event of a polio outbreak after the eradication of the wild polio virus.