National introduction of fractional-dose inactivated polio vaccine in Sri Lanka following the global "switch".

As part of the Polio eradication and endgame strategic plan 2013-2018 to achieve and sustain a polio-free world, the use of oral polio vaccine (OPV) must eventually be stopped. This process started in April 2016, with the worldwide, planned synchronized "switch", whereby use of OPV containing poliovirus type 2 ceased. Prior to the switch, in line with international guidance on risk mitigation, Sri Lanka had introduced a single full dose (0.5 mL intramuscularly) of inactivated polio vaccine (IPV) into routine immunization. However, the two global suppliers of World Health Organization (WHO)-prequalified IPV had significant challenges in scaling up production to meet the new demand, resulting in a global shortage in April 2016. The WHO Strategic Advisory Group of Experts on Immunization recommended that countries should consider a two-dose schedule of intradermal fractional IPV (fIPV). After rapid consideration of the programmatic cost and logistic implications, Sri Lanka was the first country to roll out this dose-sparing schedule nationwide. The country ensured smooth implementation of fIPV use, reaching out to all eligible infants, maintaining equity and sustaining the IPV vaccination. With expedited refresher training in intradermal vaccination, confident, well-trained and dedicated health-care staff, from the field up to provincial levels, worked together as a dedicated team. Health authorities at all levels reported that public acceptance of the additional injections of the new schedule was high. A post-introduction evaluation and an assessment of population-level immunity are under way.