The plan's US$5.5 billion budget over six years requires sustaining current yearly spending to eradicate polio. The new plan's budget includes the costs of reaching and vaccinating more than 250 million children multiple times every year, monitoring and surveillance in more than 70 countries, and securing the infrastructure that can benefit other health and development programs."Today we have the fewest cases in the fewest places ever, making it critical to use the best opportunity the world has ever had to put an end to this terrible, preventable disease," said Anne Schuchat, M.D., head of the Center for Global Health at the U.S. Centers for Disease Control and Prevention. Notes for editors: The plan was created by the GPEI in extensive consultation with national health authorities, global health initiatives, scientific experts, donors and other stakeholders . There are four main objectives of the plan: 1) Poliovirus Detection and Interruption; 2) Immunization Systems Strengthening and Oral Polio Vaccine Withdrawal; 3) Containment and Certification; and 4) Legacy Planning. Circulating vaccine-derived poliovirus: On very rare occasions, the live, weakened poliovirus contained in the oral polio vaccine may genetically alter in the immunized person's gut. If a population is seriously under-immunized, the virus may begin circulating in the community, and is referred to as a circulating vaccine-derived poliovirus (cVDPV). Between 2000 and 2011 – a period in which more than 10 billion doses of oral polio vaccine were given worldwide – cVDPV outbreaks resulted in 580 polio cases. In the same period, wild poliovirus paralyzed more than 15,500 children. As wild poliovirus declines, however, the proportion of cVDPV in low-immunity communities rises. The new plan uses cutting-edge knowledge about these viruses and new tactics to raise immunity, including introduction of inactivated polio vaccine and phasing out use of the component of the oral polio vaccine which gives rise to the majority of cVDPV. If a population is fully immunized against polio, it will be protected against the spread of both wild and vaccine strains of poliovirus.