Closing the circle: A fatal infection pushed research
'An amazingly traumatic event'
In April 1988, a young woman working in the transfusion department of the Clinical Center Hospital at the National Institutes of Health spun down a blood sample and was reaching to recap the top of the test tube. The glass tube broke, lacerating her finger and opening her blood stream to the contents of the tube. It held human immunodeficiency virus (HIV), the etiologic agent of an expanding new viral epidemic called AIDS that had laid siege to the nation's hospitals.
"Nineteen days later she had acute retroviral syndrome and two and a half years later she died," recalled David Henderson, MD, hospital epidemiologist at the NIH center for some 30 years. "If you think that isn't sobering. I saw her I don't know how many times a week as she was dying, and I felt responsible for it. It was an amazingly traumatic event for the hospital."
Of course, Henderson wasn't responsible similar incidents were occurring in other hospitals as public health officials tried to pinpoint risk factors and reduce the risk of sharps injuries and blood exposures as the epidemic unfolded. Contrary to the chronic, treatable disease often seen today, AIDS was widely viewed as a uniformly fatal infection.
"The causative agent [HIV] was unknown from 1981 until 1985," Henderson said recently in Atlanta at the Fifth Decennial International Conference on Healthcare-Associated Infections. "During that time we had more than 500 patients often very sick patients with this disease at my hospital. Health care epidemiology programs around the country began [trying] to define the risk for occupational infection in health care workers. The nosocomial epidemiology of this disease was really pretty much uncertain until the late 1980s, and it contributed substantially to staff angst."
But Henderson worked in the NIH clinical center after all a one-of-a-kind research hospital where hundreds of clinical trials are underway at any given moment. One of them at that time involved an agent called BW A509U, which was showing some early potential for blocking HIV infection after exposures to infected blood. At that time, no post-exposure prophylaxis (PEP) existed, and part of the frustration felt by Henderson and other epidemiologists and infection preventionists was that there were so few options for exposed health care workers.
Henderson supported the idea of using the new drug as a PEP agent, drawing some flak from public health officials for getting out in front of the other agencies. "We started offering the drug," he said. "I took a lot of heat from my friends in Atlanta for doing that. It was not popular for the NIH to get out there on issues like this when CDC was carrying the ball."
However, through the work of Henderson and others, the public health service felt safe enough with the new drug which came to be known as zidovudine to cautiously endorse its use for PEP. A 1997 published case-control study showed the striking efficacy of zidovudine, which reduced the risk of HIV infection by 81% in exposed health care workers.1 Henderson wrote the accompanying editorial, which he dedicated to his fallen colleague.2 "I felt like we had finally closed the circle on that event," he said.
As risk factors became more clearly understood, prevention efforts steadily lowered the risk of exposures in health care workers. PEP became a powerful weapon if they did occur. Henderson was selected at the Decennial meeting to deliver the annual lecture for the Society of Healthcare Epidemiology of America. The honor recognizes career contributions, which in Henderson's case include a leading line of research on the risk of HIV acquisition following a single exposure to infected blood.
"It was a small number .325%," he said. "What a small number for a bloodborne viral infection."
- Cardo DM, Culver, DH, Ciesielski, CA. A Case–Control Study of HIV Seroconversion in Health Care Workers after Percutaneous Exposure. New Eng Jrl Med. 1997; 337:1485-1490.
- Henderson, DK. Postexposure Treatment of HIV Taking Some Risks for Safety's Sake. Editorial. New Eng Jrl Med. 1997; 337:1542-1543.