KATHMANDU, Nepal — In April at Mount Everest base camp, where climbers acclimatize to the extreme altitude before heading to the summit of the world’s highest peak, Jangbu Sherpa fell ill with a cough and fever.
At 17,590 feet, his symptoms quickly worsened. The expedition company that had hired Mr. Sherpa to help a Bahraini prince climb Everest had him airlifted to a hospital in the capital, Kathmandu, where he tested positive for the coronavirus.
He spent a week at the hospital and six days at home, and then was back at base camp. Experienced guides like him from Nepal’s high-mountain-dwelling Sherpa community were in short supply because of the pandemic, and the expedition company stood to lose thousands of dollars if the prince’s climb were canceled.
So, with his body still fighting the vestiges of the virus, Mr. Sherpa, 38, most likely became the first person with Covid-19 to stand on Everest’s pinnacle when he led the prince and 15 others there at dawn on May 11. By the end of the climbing season early this month, at least 59 infected people had been on the mountain, including five others who reached the top, according to interviews with climbers and expedition companies and the personal accounts of social media users.
“Were Sherpas and climbers supermen?” said Ang Tshering Sherpa, a former president of the Nepal Mountaineering Association. “This issue deserves in-depth research.”
But according to the Nepal government, there was never any Covid-19 on Everest. Tourism officials dismissed the accounts of climbers, calling one a pneumonia patient. Coughing, they added, is nothing new in the dry mountain air.
Nepal’s tourism department, which oversees Everest expeditions, maintained this position even as people were being airlifted off the mountain and expeditions were being canceled — a rare event because of the great expense and effort made to train, travel to Nepal and try to summit Everest.
In April, a Norwegian climber, Erlend Ness; a British climber, Steve Davis; and others wrote on social media about having Covid-19 during their Everest expeditions.
“From 2 hospitals last 3 days. Today I will have a PCR test. Hope to leave the hospital soon,” Mr. Ness wrote on Facebook, posting a photo of himself in a mask in a hospital bed.
Nepal, one of the world’s poorest countries, has been struggling with a dire coronavirus outbreak and a shortage of vaccines. Few Sherpas or other Nepalis had access to vaccines while the climbing season was underway; even now, as the government pleads with wealthy nations for doses, less than 3 percent of the population has been fully inoculated.
Officials had strong incentives to play down the Covid situation on Everest. Nepal closed its peaks in 2020 because of the pandemic, after bringing in more than $2 billion from climbing and trekking in 2019. If the Covid-19 cases were publicized, it could tarnish Nepal’s image as a tourist destination, and invite climbers whose expeditions were canceled to demand extensions of their climbing permits.
Still, with this year’s climbing season now over, more expedition agencies are acknowledging that Covid-19 infections were rampant in the crowded base camp, which drew a record 408 foreign climbers this year. The true number of cases could be far higher than 59, since expedition organizers, doctors and climbers themselves said they were pressured to hide infections.
The Nepal government had made some preparation to avoid infections on the mountain. It instituted testing, mask and social-distancing requirements, stationed medical personnel at the Everest base camp and had helicopters ready to swoop in and pick up infected climbers.
Expedition companies, which often bring their own medical personnel, also packed antigen kits, testing members of their groups regularly and isolating anyone who tested positive.
Given that all climbers had to test negative before starting the trek to base camp, it is likely that most of those with Covid-19 became infected while on the mountain, though it is possible that some arrived with infections that were not initially detected.
There were compelling reasons for expedition companies to proceed with climbs, even as the first coronavirus cases were reported at base camp from the last week of April to the first week of May.
They had laid out more than 60 percent of their budgets. The government of Nepal had received $4.6 million in royalties. Sherpas and support staff were deployed. Ropes were soon to be fixed in place. Food, cooking gas and other supplies had been hauled up by workers and yaks to the makeshift city of colorful tents where climbers stay for 40 days, allowing their lungs to adjust to the altitude and waiting for a window of clear weather to make the ascent.
Multiple Sherpas and expedition companies interviewed by The New York Times said that at least three or four people from each expedition group were eventually infected during their stay at base camp.
Lukas Furtenbach of Furtenbach Adventures, which canceled its expedition, sending climbers back to Kathmandu before they could attempt to summit Everest, estimated that the tally was far higher than The Times’s count.
His company’s expedition ended after an American climber and three Sherpa guides were evacuated from base camp to the capital, where they were hospitalized for Covid-19. Mr. Furtenbach has written to Nepal’s tourism department requesting that the government extend his climbers’ permits by two years.
Rudra Singh Tamang, the director general of the tourism department, said he had no information about Mr. Furtenbach’s appeal or those of other expedition agencies sent to his office to extend climbing permits.
“We can’t just extend climbing permits on basis of Covid rumors,” Mr. Tamang said.
“Whether their expeditions were canceled because of Covid-19 or not, that should be examined,” he said.
With very few Sherpas having been vaccinated when they arrived at base camp, dozens contracted Covid-19. Some were airlifted out. Others isolated in their pup tents and climbed to higher camps after recovering.
Phunuru Sherpa of International Mountain Guides said 10 Sherpa guides on his team fell sick with Covid-19.
Of the more than 400 foreign climbers attempting to scale Everest, almost half abandoned their expeditions, either because of Covid-19 infections or because of a cyclone that caused snowstorms in the Himalayas.
Scott Simper, a climber from Utah who lives in New Zealand, reached Everest’s peak on May 11, according to his wife, Anna Keeling, a mountain guide.
“He didn’t know he had Covid on the mountain,” she said. Mr. Simper learned of his infection only after testing positive days later in Kathmandu, where his expedition company quarantined him at a hotel for 12 days. His wife said he was still recovering from the disease.
Mr. Ness, the Norwegian climber who described his bout with Covid-19 on social media, was airlifted from base camp to a hospital in Kathmandu. Doctors advised him not to return to the mountain, so he flew home to Norway. The Everest expedition had taken three years to plan and cost him $40,000, plus hospital fees in Nepal. He does not expect to get any money back.
Mario Celinic of Croatia said he tested positive at Everest base camp. He had trained for Everest for four years, climbing some of the world’s other highest peaks. Suffering no symptoms, he decided to proceed to the top.
“‘You have Covid and you must be careful,’ this came into my mind, because Covid affects the lungs and that would be difficult to breathe above 8,000 meters’ altitude,” he said.
“That mountain is like a beautiful flower that will kill you anytime. It attracts you. You must come, you are admired. And when you go up to 8,000 meters, you are completely helpless. Whatever the mountain decides, that will be your fate,” Mr. Celinic said.
Bhadra Sharma reported from Kathmandu, and Emily Schmall from New Delhi.