SPRINGFIELD, Va. -- The number of deaths associated with a respiratory outbreak at a Fairfax County assisted living facility has risen to three, according to the Fairfax County Health Department.

Since the first case was reported on June 30, 63 of 263 residents at Greenspring Retirement Community, a long-term care facility with assisted living, have become ill with respiratory symptoms ranging from upper cough to pneumonia.

Health officials say there have been 20 hospitalizations and three deaths associated with the outbreak.

Health officials explained that they do not know the full medical history and the extent to which the respiratory illness contributed to the deaths.

In addition, the Health Department has been informed that 19 employees have also reported symptoms of upper respiratory illness.

A specific cause has not yet been identified and results of testing by the Centers for Disease Control and Prevention (CDC) are still pending, said the Fairfax County Health Department.

Those officials say respiratory outbreaks at facilities for vulnerable, older adult populations are not uncommon. The department said they typically see about 12 per year. However, this particular outbreak is different because most outbreaks of this kind are in the winter or during flu season.

Greenspring Retirement Community is not taking new residents as the outbreak is investigated, according to WUSA.

In a statement, Greenspring said it's "highest priority is the welfare of those who live and work on campus."

"In keeping with this commitment the community has acted with an abundance of caution, and in partnership with the Fairfax County Department of Health, has taken all necessary measures to fully implement proven infection prevention and control strategies," the statement said.