BRASILIA, Nov 17 (Reuters) - COVID-19 deaths have decreased 17% in the Americas over the past week, but the most populous countries like the United States, Brazil and Colombia are seeing a leveling of new infections after weeks of declining trends, the Pan American Health Organization (PAHO) said on Wednesday. Mexico is reporting an increase in new deaths and in the Caribbean Trinidad and Tobago had a sharp rise in deaths as intensive care unit (ICU) beds fill with COVID-19 patients, PAHO said. In an important milestone, half of the people in Latin America and the Caribbean have now been fully vaccinated against COVID-19, though coverage remains below 10% in Nicaragua and Haiti, PAHO Director Carissa Etienne said. "The COVID pandemic is still very active in our region," she warned in a webcast news conference. Countries across Central and South America have seen a decline in new infections, except for Bolivia, it said. As Uruguay and Chile have relaxed pandemic restrictions, COVID-19 cases have spiked, even with their high vaccination coverage, the health agency said. Etienne urged people in the region to get vaccinated and stick to social distancing and mask wearing as the holiday season approaches. Reporting by Anthony Boadle Editing by Bill Berkrot Our Standards: The Thomson Reuters Trust Principles.