A woman receives her first dose of China's Sinovac Biotech vaccine during a mass vaccination program for the elderly at Movistar Arena in Bogota on March 9. — Reuters UNITED NATIONS: Enabling poorer countries to make Covid-19 vaccines is the only effective way of defeating the pandemic that has already killed almost three million people, says a UN report released on Monday. The United Nations has launched a global campaign called COVAX to get two billion vaccine doses to inoculate around a quarter of the world’s poor by the end of 2021. The report — “How can we vaccinate the world” — reviews the main challenges the campaign faces and suggests five major steps to overcome those challenges.