Growing up in the United States Virgin Islands, Dr. Marcella Nunez-Smith saw firsthand what can happen in a community with limited access to health care. Her father, Moleto “Bishop” Smith Sr., was only in his 40s when he suffered a debilitating stroke that left him partly paralyzed and with slurred speech.

The cause was high blood pressure, which could have been treated but had never been diagnosed. Without prompt access to advanced treatments, “the stroke was allowed to run its course,” Dr. Nunez-Smith, 45, recalled in a recent interview. Her father never fully recovered.

Across New York State, medical providers in recent weeks had the same story: They had been forced to throw out precious vaccine doses because of difficulties finding patients who matched precisely with the state’s strict vaccination guidelines — and the steep penalties they would face had they made a mistake.

On Saturday, state health officials responded to the outcry over discarded vaccines by again abruptly loosening guidelines as coronavirus cases continued to rise.

Now, medical providers can administer the vaccine to any of their employees who interact with the public if there are extra doses in a vial and no one from “the priority population can come in before the doses expire,” the new guidelines read. A pharmacy’s “store clerks, cashiers, stock workers and delivery staff” could qualify, the guidelines said. California last week took a similar step.

DURBAN, South Africa — Doctors and nurses at a South African hospital group noticed an odd spike in the number of Covid-19 patients in their wards in late October. The government had slackened its lockdown grip, and springtime had brought more parties. But the numbers were growing too quickly to easily explain, prompting a distressing question.

“Is this a different strain?” one hospital official asked in a group email in early November, raising the possibility that the virus had developed a dangerous mutation.