The United States has lifted a 22-year immigration ban which has stopped anyone with HIV/AIDS from entering the country. President Obama said the ban was not compatible with US plans to be a leader in the fight against the disease. The US plans to host a bi-annual global HIV/Aids summit for the first time in 2012. The new rules come into force from today. The ban was imposed at the height of a global panic about the disease in 1980.