In April, Parton announced she was giving the money to Vanderbilt University Medical Center in Nashville.
That was one of the trial sites for the Moderna vaccine, which is nearly 95% effective, according to early data.
A Vanderbilt spokesperson said Parton's "generous" gift was helping "several promising research initiatives".
A portion of the singer's money went towards funding an early stage trial of the Moderna vaccine.
'Very promising research'
Her donation is also supporting a convalescent plasma study and research involving antibody therapies, Vanderbilt University Medical Center spokesperson John Howser said.
Convalescent plasma is used to treat people who are battling a Covid infection.
"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."
Vanderbilt's plasma pilot showed enough promise for the US NIH (National Institutes of Health) to step in with $34m (£26m) in additional support to conduct a national, multi-site clinical trial into the benefits of convalescent plasma.