Timely vaccination is key to maintaining population immunity against vaccine-preventable diseases (VPDs), ensuring populations are fully protected against life-threatening illnesses as early as possible, and preventing large outbreaks of VPDs. However, scheduled vaccinations may be missed for a number of context-specific reasons (e.g. difficulty accessing health services and other health system barriers, health worker practices, stock outs, beliefs held by caregivers and community members about vaccination, etc.)
No one should miss out on the right to the protection that vaccines offer, simply because they are unable to access services in time.A catch-up vaccination strategy (which includes a clearly defined catch-up vaccination policy and catch-up schedule) is an essential part of a well-functioning national immunization programme and should be implemented on a continuous basis.
