Climbers have begun to make the treacherous, windswept ascent toward the summit of Mount Everest despite concerns over a possible coronavirus outbreak at their camp at the base of the world’s tallest peak.

After a team of 12 Sherpa guides affixed a rope to the summit on Friday evening, climbers set off from the base camp on Nepal’s side of the mountain in the first expedition to try to reach the five-and-a-half-mile-high summit since 2019.

Nepal closed its lucrative Himalayan mountaineering industry in 2020 because of the pandemic. As part of the government’s effort to revive the country’s overall $2 billion tourism industry this year, it issued 408 permits for Everest climbs, the most ever, even as the virus began surging across the country.

Nepal, which shares a long border with India, recorded more than 9,100 cases on Friday, compared to a daily average of fewer than 100 one month ago.

Several climbers at Nepali base camp have fallen ill and been evacuated in recent weeks. Upon returning to Kathmandu, the capital, some have tested positive for the coronavirus and shared their accounts on social media — even as Nepal tourism officials deny there have been any infections on Everest.

Despite the reports of infections, local guides spent weeks affixing a rope to help guide climbers to the peak. The team was led by Kami Rita Sherpa, who reached the summit of Everest for a record-breaking 25th time on Friday, said Mingma Sherpa, the chairman of Seven Summit Treks, Nepal’s largest expedition operator.

A team of climbers, including a Bahraini prince, has departed for the summit, he added, and is expected to reach the peak on Tuesday.

New York Times News Service