The mandate includes physicians, dentists, nurses and others who work in patient-facing roles.
"We’re mandating vaccines for Title 38 employees because it’s the best way to keep veterans safe, especially as the delta variant spreads across the country," McDonough said Monday.
"Whenever a veteran or a VA employee sets foot in a VA facility, they deserve to know that we have done everything in our power to protect them from COVID-19," he continued. "With this mandate, we can once again make – and keep – that fundamental promise."
An administration official stressed the importance of the move, saying it was imperative for patients to feel safe and not risk getting COVID from their health care providers. At this point, the Department of Veterans Affairs is the only federal agency that will require some employees to be vaccinated.
The announcement comes after the VA lost four employees to COVID-19 in recent weeks. All four were unvaccinated. The agency said at least three of the employees died due to the delta variant of the novel coronavirus.
The announcement also comes amid an outbreak among unvaccinated employees and trainees at a VA Law Enforcement Training Center, which the VA says it the third such outbreak during the pandemic.
The agency stressed Monday that all VA employees are eligible to be vaccinated "at no personal expense at any of our facilities."
The department said employees would also receive four hours of paid administrative leave after demonstrating that they have been vaccinated.
"The safety and well-being of our veterans and personnel is paramount," the VA said in a statement Monday.