BOGOTÁ, Colombia — In the capital of Colombia, Bogotá, the mayor is warning residents to brace for “the worst two weeks of our lives.”

Uruguay, once lauded as a model for keeping the coronavirus under control, now has one of the highest death rates in the world, while the grim daily tallies of the dead have hit records in Argentina, Brazil, Colombia and Peru in recent days.

With India preparing to make residents 18 and older eligible for a coronavirus vaccine starting Saturday, Dr. Aqsa Shaikh emailed the country’s largest drug manufacturer this week asking for doses for the vaccination center she runs in New Delhi.

The response was not encouraging: The company, the Serum Institute of India, said it was so overwhelmed by demand that it could take five or six months for Dr. Shaikh to get the 3,000 doses per month she requested.

“When I read that email, images of mass burials appeared in front of my eyes,” she said. “We may have to shut down the center now if the government doesn’t chip in.”