São Paulo says it has fully vaccinated more than 100 percent of its adults. Will it be enough to stop omicron?

In a world struggling to convince people to take the coronavirus vaccine, the news was striking. São Paulo, the largest city in the Western Hemisphere, announced late last month that it had succeeded where others had failed. One hundred percent of its adult population had been fully vaccinated against the coronavirus — a remarkable rate in an era characterized by an intransigent and growing global anti-vaccine movement that has hobbled vaccination efforts from Europe to the United States.