On the day he was scheduled for a COVID-19 vaccination, 77-year-old Jaikishan Ram wrapped himself in a well-worn wool jacket, cap, and sweater to prepare for the three-hour trek down the mountain.

To access the main road from his home high in the Himalayan mountains of the Indian state of Uttarakhand, Ram had to first climb down a mile of steep, unpaved, sloping path. From there, it was another 90 minutes on the main road to the village of Padampuri. That’s where the only government hospital and walk-in COVID-19 vaccination center in the Dhari area—home to some 30,000 people spread across 46 villages—is located.

It was early September, and India was still recovering from a devastating second COVID-19 wave, driven primarily by the Delta variant. According to…