Twenty-eight National Institutes of Health staff members have tested positive for COVID-19, as of March 27.
An NIH spokesperson would not say which institutes the affected staffers worked for or whether they worked in one department or were scattered throughout NIH.
The 28 cases are listed as part of the Montgomery County total numbers as the NIH headquarters is in Bethesda.
NIH is monitoring the staff and those who believe they came in close contact to those who tested positive are asked to self-quarantine at home.
When a staff member tests positive, that NIH facility temporarily is closed off and then disinfected, according to the NIH.
Beginning on March 12 and continuing until at least May 1, NIH staffers who are eligible are encouraged to work from home as much as possible.
Some employees working on non-mission critical functions throughout NIH laboratories have been shifted to critical functions, including care of research participants in clinical studies that are non-elective, research on COVID-19 and urgent public health research.
Those caring for research animals also are considered critical employees.