 The oral polio vaccine must be kept at for vaccination to be successful.An independent evaluation of obstacles to polio eradication requested by the WHO and conducted in 2009 considered the major obstacles in detail by country.In Afghanistan and Pakistan, they concluded that the most significant barrier was insecurity; but that managing human resources, political pressures, the movement of large populations between and within both countries, inadequately resourced health facilities, also posed problems, as well as technical issues with the vaccine.