The captain enjoyed a trip to Barbados with his family in December before lockdown restrictions were tightened.
However, his family's spokesperson has revealed that Captain Tom had tested negative for coronavirus until he was treated for pneumonia.
He tested positive for COVID-19 the day he was discharged from hospital after a ten-day stay last month.
A statement from his family read: "He was admitted to hospital on January 12. Whilst in hospital he received a pneumonia diagnosis.
WATCH: Piers Morgan hits out at critics of Captain Sir Tom Moore
"In addition, as with other patients, he was tested regularly for Covid-19.
"On January 22, Tom was discharged from hospital back to the family home where he felt most comfortable. Unfortunately he was left still fighting pneumonia and tested positive for Covid-19 that day.
"He remained at home, cared for by family and medical professionals, until he needed additional help with his breathing. He was taken by ambulance to Bedford Hospital on Sunday January 31."
The Queen knighted Captain Sir Tom last year
The statement went on to say that the NHS champion said goodbye to his loved ones before his death.
It read: "Tom was able to have visitors to say goodbye to him at the end of his life. On Monday evening his daughter Hannah and grandchildren Benjie and Georgia were able to be by his side and his daughter Lucy was able to speak to him on FaceTime."
Captain Sir Tom raised more than £32 million in 2020 by hitting his target to walk the length of his garden 100 times in honour of his 100th birthday, completing his challenge last April.
He donated the money raised to NHS Charities Together to help frontline workers dealing with the pandemic. He was knighted by the Queen on 17 July 2020 at Windsor Castle.
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.