Double-deadly needlestick transmits HIV and HCV
Delayed seroconversion raises follow-up questions
The first documented case of simultaneous transmission of HIV and hepatitis C virus (HCV) from a single needlestick has occurred, leading to the death of the infected health care worker, the Centers for Disease Control and Prevention reports.
Unusual features of the case -- including delayed onset of initial symptoms, late seroconversion for both HIV and HCV, and then rapid progression to HCV disease and death -- may have resulted from the interaction of the two viruses, said Renee Ridzon, MD, medical epidemiologist at the CDC. She reported the case recently in Washington, DC, at the annual conference of the Society for Healthcare Epidemiology of America (SHEA).
Delayed seroconversion
With HCV increasingly becoming a threat to health care workers, the case of dual occupational infection may not remain an anomaly. In that regard, the delayed seroconversion in the case raised some troubling exposure follow-up questions, particularly whether such cases will be missed by hospitals that stop post-exposure testing at six months.
The case began in July 1990, when a healthy 46-year-old female worker in Massachusetts sustained a deep needlestick injury from an HIV/HCV-infected source patient. The worker declined zidovudine prophylaxis. Eight months later, the worker had acute onset of hepatitis. The intervals from exposure to HIV seroconversion, and to onset of acute HCV are the longest that have been reported to CDC, yet the subsequent progression to cirrhosis and liver failure was more rapid than usually occurs with HCV infection.
In particular, the case immediately raised questions about HIV follow-up because the health care worker seroconverted after the widely accepted six-month window used by many hospitals. Seroconversion for HIV occurred between eight and 9.5 months post-exposure, and for HCV between 10.5 and 13.5 months post-exposure.
"The medical course of this health care worker seemed to be dictated by the HCV infection rather than the HIV infection," Ridzon said, noting that death from HCV occurred 28 months post-exposure without the appearance of any AIDS-defining conditions.
'A remarkable case'
Asked whether the case may warrant extending routine post-exposure testing for HIV out to one year, Ridzon said policy changes should not be made based on one such case.
"However, I think it is a very remarkable case, and it deserves attention and thought," she said. "You can say this is unusual and is going to be way out on the bell-shaped curve. But on the other hand, when health care workers are exposed, I don't know how many actually are followed up this far out."
Epidemiologic models indicate 95% of seroconversions for HIV will occur within the first six months following exposure, noted David Bell, MD, chief of the HIV infections branch in the CDC hospital infections program. In discussing the case at SHEA, he emphasized, however, that did not mean the risk for seroconversion following a needlestick would be 5% after six months. The risk of seroconversion from a needlestick from HIV-infected blood remains 0.3%.
"A negative test at six months still carries very high predictive value," Bell said. "We still recommend that [HIV] exposures be followed serologically for a minimum of six months." *
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