Estimates of the magnitude of the problem vary wildly. A paper by Dr. Ranjith Ramasamy, director of reproductive urology at the University of Miami’s Desai Sethi Urology Institute, and his colleagues found that the risk of erectile dysfunction increased by 20 percent after a bout with Covid. Other investigators have reported substantially higher increases in that risk.

When patients first started coming to Dr. Ramasamy’s clinic complaining of erection problems, “We dismissed it, thinking it was all psychological or stress induced,” he said.

But over time, he and other physicians began to see a pattern, he said. “Six months after the initial infection, patients had gotten better overall, but they continued to complain of these problems,’’ including both erectile dysfunction and low sperm counts, Dr. Ramasamy, who has written several papers on the topic, said.