Surging COVID-19 cases in parts of South America are overwhelming some health systems, demanding a quick response, though infections continue to drop in other countries in the Americas region, the head of the Pan American Health Organization (PAHO) said today.In other global developments, Colombia, Cambodia, and several more countries in Africa received their first vaccine shipments though COVAX, a program led by the WHO and its partners that is designed to provide equitable access to vaccines, a key tool for driving down virus levels in all parts of the world.Health systems struggle in Amazon basinAt a briefing today, Carissa Etienne, MBBS, MSc, said the mixed picture of country situations in the Americas is a reminder of how deadly