Form VOA Learning English ,this is the health report .Most countries are now free of polio, but the disease remains a threat in some countries lucluding Nigeria. Gregory hussy is the direstor of the vaccines of Africa Initiative at the university of Cape Town in South Africa. He says there is a worldwide movement to eradicate polio in the next five to 10 years. He says there are problems in Nigeria because people are refusing to immunize their children for a number of reasons. The world Heath Organization says after polio vaccination campaigns were interfered with in northern Nigeria several years ago, the virus there spread all the way to Ethiopia. Gregory Hussey says continved outbreaks of measles represent another failure. The United Nations and other international agencies have immunization campaigns But Africa lacks its owa major programs. The Vaccines for Africa Initiative was started to spread knowledge about vaccines not only to healthcare worker, but to policymakers and communities. But Gregory Hussey says cost remains a major problem. An international pubic - pvivate partnership , the GAVI Alliance , helps developing countries offer vaccines. But Gregory Hussey warns that low-cost vassines will not be available forever. He says some countries the have enovgh money to vassinate clildren have not made the a top goal. Researchers at the University of Cape Town say African leaders must be held accountable for meeting immunization targets and honoring international commitments. Form VOA Learning English, I’m Laurel Bowman.