Hopps worked as a bacteriologist at Garfield Memorial Hospital and then Walter Reed Army Institute of Research. She joined the National Institutes of Health (NIH) in 1956, first in the National Institute of Allergy and Infectious Diseases. In 1960, she joined the NIH Division of Biologics Standards (DBS) in the Laboratory of Viral Immunology. There she worked with Drs. Paul Parkman and Harry Meyer on the rubella vaccine and the patented rubella antibody test.

Hopps authored or co-authored more than 89 articles, was awarded two patents, including one for the BS-C-1 continuous cell line that she developed from African green monkey kidney cells. The BS-C-1 continuous cell line is still used today and is suitable for propagating several viruses, including polio, measles, Rift Valley fever, respiratory syncytial, Coxsackie A9, O'Malley's A-1 agent, and simian agents 1, 4 and 5. Thanks to her work, the BS-C-1 continuous cell line provides virologists another tool for diagnostic and research work and perhaps for the large-scale cultivation of viral agents for vaccines.

She was the national president of Graduate Women in Science.

After the transfer of biologics from the NIH to the Food and Drug Administration (FDA) in 1972, Hopps also became an administrator,  first as the assistant to the Director of Biologics and then as acting associate director for Program Development and Operations, working in Building 29.

After retiring from government service, Hopps continued to work as a consultant and guest worker in the FDA’s Center for Drugs and Biologics.

See also, “Finding Hope: A Woman’s Place Is In The Lab” Exhibition.