In the first big test of Covid- 19 vaccines during a Covid-19 surge, places with higher vaccination rates are dodging the worst outcomes so far, while cases and hospitalizations surge in less-vaccinated areas.

There are more tests yet to come, including when cold weather forces people in the well-vaccinated Northeast back indoors. But as the highly contagious Delta strain tears through the country, the trends thus far suggest vaccines can turn Covid-19 into a less dangerous, more manageable disease.

“Vaccines definitely make a difference,” said David Dowdy, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.

A Wall Street Journal analysis shows sharp geographic divides in vaccination and hospitalization levels, with every state that has an above-average vaccine rate showing below-average hospitalizations, including in well-vaccinated New England. In the South, meanwhile, fewer people are vaccinated on average and hospitalization rates are climbing faster.