LONDON — Capt. Sir Tom Moore, the 100-year-old hero who raised almost $45 million for Britain’s National Health Service by repeatedly walking the length of his garden during the nationwide lockdown last year, has been admitted to a hospital with the coronavirus, his family announced Sunday.

Posting to his official Twitter account, Moore’s daughter Hannah Ingram-Moore said the veteran, who was knighted by Queen Elizabeth II for his efforts last year, had spent the past few weeks being treated for pneumonia and tested positive for the coronavirus last week.

“He was at home with us until today when he needed additional help with his breathing,” she explained Sunday, adding he was being treated at Bedford Hospital in England but was not in the intensive care unit. The family, she said, hoped he would be back home with his loved ones soon.

Moore is not believed to have been vaccinated against the virus because of the medication he is receiving for his ongoing battle with pneumonia, British media reported Monday.

Moore’s walking story — and unexpected rise to stardom — began in April last year when he sought to raise 1,000 pounds (nearly $1,372) for the NHS by walking his 82-foot long garden back and forth 100 times, using his walker for support.

He wanted to complete the laps, which he broke down into chunks, ahead of his 100th birthday on April 30.

As public interest in his fundraiser grew, so did the pot of donations. Just 24 hours after Moore started walking, he had raised the equivalent of $8,750. As funds poured in, Moore’s fundraising page crashed repeatedly.

The veteran, who was born in 1920, completed his final lap two weeks ahead of schedule — an event that was live-streamed by the BBC as the figure reached $15 million. To date, the total stands at more than $40 million.

Health workers across the country who have long called for better funding from the government hailed Moore’s money-raising efforts during a crisis that has claimed at least 106,000 lives in Britain.

The British government has long been criticized for its handling of the pandemic, with many accusing officials of not locking down the country sooner and failing to supply health-care workers with sufficient protection and access to test kits.

“They’re all being so brave. Every day, they’re putting themselves in danger of this unseen enemy that we’ve got at the moment,” Moore said of doctors and nurses in an interview with Sky News Australia last year.

In December, British Airways said it was an honor to pay for Moore and his family to fly to Barbados — a destination that had been on the grandfather’s wish list for some time.

“The support I have been shown in 2020 has given me renewed energy and today I get to tick something off my bucket list,” Moore tweeted in December alongside a photo of him and his family on the island — although some on social media questioned the suitability of this vacation with the coronavirus crisis raging on.

Within minutes of the family’s announcement about Moore’s hospitalization being shared, however, well-wishes flooded in from around the world as his name began to trend on social media.

Prime Minister Boris Johnson wished Moore a full recovery, adding he had “inspired the whole nation,” while London Mayor Sadiq Khan thanked the NHS for taking care of the widely loved and respected centenarian. “Hoping for a speedy recovery and to see Captain Tom back home with his family soon.”

Helen Whately, junior health minister, told Sky News that Moore had been a shining light for Britons during a period of darkness. “He’s really lifted our spirits,” she said. “I really hope he pulls through.”

Last year, Moore, who quickly became a national treasure, was treated on his 100th birthday with a Royal Air Force flyby above his home in Bedfordshire, 50 miles north of London, as street art of his face began appearing around the country.

Children and fans sent him more than 150,000 birthday cards and a tribute flashed on the big screen in Piccadilly Circus.

Prince William, who is second in line to the British throne, branded Moore a “one-man fundraising machine.”