SEVERAL WEEKS ago, Republican Gov. Larry Hogan of Maryland lifted pandemic capacity restrictions on restaurants, bars and some other public places, saying “the time is right” after the winter surge in infections had dissipated. Mr. Hogan properly kept the mask mandate in place. But his reopening decision looks to have been premature. Coronavirus daily case counts are on the rise again.

Mr. Hogan’s restrictions were lifted effective March 12, when the seven-day moving average of daily new cases in Maryland was 860. Late this week, it reached a single-day total of 1,584. When Mr. Hogan made his announcement on March 9, the state’s test positivity rate was 3.4 percent. On a seven-day average it is now 4.3 percent. Montgomery and Prince George’s counties, which decided to keep most of their restrictions in place, have not seen a similar jump in cases, though Prince George’s has faced an uptick.

When he ordered the reopenings, Mr. Hogan pledged to “follow the science” and remain “prudent.” But this week, he was in denial. “We don’t think it had anything to do with reopenings,” he said, attributing the upward swing in cases to travel. No question, travel contributes to it. So do the more-contagious variants, such as the B.1.1.7 first discovered in Britain, now spreading through Maryland. But Mr. Hogan should realize that the reopening and the other factors are now propelling the state’s case count in the wrong direction.

Maryland and the rest of the country are in a race against time to get enough people vaccinated to avoid a fourth wave of pandemic suffering. Hot spots in the Northeast and Michigan prompted the director of the Centers for Disease Control and Prevention, Dr. Rochelle Walensky, to implore jurisdictions to keep restrictions in place. “I’m going to reflect on the recurring feeling I have of impending doom,” she told a news briefing. “We have so much reason for hope, but right now I’m scared.”

There are plenty of reasons to be worried. Abroad, the pandemic is raging in parts of Europe, and out of control in Brazil. In Michigan, Gov. Gretchen Whitmer, a Democrat, decided in March to allow restaurants to operate at higher capacities. Infections in the state have exploded, both in rural areas and cities, from an average of 1,388 per day on March 1 to 7,437 on April 1. One surprising exception is Texas, where Republican Gov. Greg Abbott lifted most of the state’s restrictions on March 2 and case counts have subsequently declined. This may reflect individual decisions of people to continue wearing masks anyway.

It is a fact that enclosed spaces such as bars and restaurants can be extremely hazardous for transmission of the virus when people are unprotected, and even more so with the B.1.1.7 variant on the move. The ability to brake the pandemic is within our grasp; vaccines and migitation measures will work. Mr. Hogan should heed his own promise to “follow the science” and not hesitate to reimpose restrictions if necessary to stop a fourth wave in Maryland.

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