Singer Dolly Parton is being hailed as a somewhat unlikely hero in the fight against the pandemic.

Back in April, Parton donated $US1 million ($A1.4 million) to the Vanderbilt Medical Centre in Nashville.

The centre is one of the trial sites for the Moderna vaccine, and some of her cash was used to fund an early stage of the trial.

Just this week, researchers said Moderna’s vaccine had been found to be 94.5 per cent effective against the deadly virus that has killed more than 250,000 Americans.

Tweet from @DollyParton

A Vanderbilt spokesman said Parton’s “generous” gift had helped fund “several promising research initiatives”.

The singer’s money was also helping to pay for a convalescent plasma study and research involving antibody therapies, Vanderbilt University Medical Centre spokesperson John Howser said.

Convalescent plasma is used to treat people with COVID.

“Her gift provided support for a pilot convalescent plasma study that one of our researchers was able to successfully complete,” Mr Howser told BBC News.

“Funds from Dolly’s gift are also supporting very promising research into monoclonal antibodies that act as a temporary vaccine for COVID. Two of these antibodies are now being tested by a global pharmaceutical firm.”

Tweet from @ErikOJensen

Parton, who lives just outside Nashville, is a known philanthropist. Many of her donations are made anonymously.

But she was outspoken in 2007 when donating $500,000 to the new Fort Sanders Sevier Medical Centre in the Tennessee county where she was born.

The then 61-year-old told fans at a benefit concert that she was much less important than the new hospital – not only because “all of my family has been down there at one time or another” but also because of the country doctor who brought her into the world.

“He’s the one that rode on horseback so many years ago, when I was a young’un back in them mountains,” she said of Dr. Robert F. Thomas.

“I was born and paid for with a sack of cornmeal.”

Parton’s other favourite causes are literacy and the environment. The Imagination Library she established in 1995 sends a book every month to children from the time of their birth until they enter kindergarten.

In 2003, her efforts to preserve the bald eagle through the American Eagle Foundation’s sanctuary at Dollywood earned her the Partnership Award from the US Fish and Wildlife Service.