Special Report: Frontline HCWs
Occupational HCV a 40-fold greater threat than HIV?
When national prevalence figures and the risk of transmission per exposure are factored in, hepatitis C virus (HCV) may represent a 40-fold greater threat to health care workers than HIV, a medical epidemiologist reported at the recent Frontline Health Care Workers conference in Washington, DC.
In the United States there are approximately four million people infected with HCV compared to one million with HIV, explained Robert Ball, MD, MPH, infectious disease consultant epidemiologist at the South Carolina Department of Health in Columbia.
Coupled with that quadruple prevalence is a 10-fold difference between the viruses in risk of transmission per needlestick exposure, he noted, citing a .3% risk of transmission for HIV and 3% for HCV.
"It is fair to say that the risk to health care workers per exposure of HCV relative to HIV is 40-fold greater," Ball told conference attendees. "I haven't seen that figure articulated quite in that way before, but it makes sense when you think about it, with four times the prevalence and 10 times the risk per positive exposure. This is something that might be a bit of an eye-opener to our risk managers and our CEOs."
HCV, an RNA virus, mutates almost as frequently as HIV, which means it will likely be quite a while before a vaccine is developed, he said.
"Its hypermutability enables it to foil our immune defenses," he said.
Once infected, about 70% to 85% of cases become chronic, and nearly all chronic cases persist lifelong, he noted. Current data suggest that the annual incidence in the United States is between 35,000 and 180,000 cases of acute HCV each year. Ball estimated that about 1.5% of all health care workers are infected, with about 2,000 contracting HCV annually. According to the Centers for Disease Control and Prevention, chronic HCV causes between 8,000 and 10,000 deaths annually and leads to about 1,000 liver transplants.
Interferon can effectively clear some HCV infections, but it carries the risk of devastating psychological side effects in some recipients, Ball explained. For example, he described a case study of a popular and outgoing housekeeper in her 40s who has become depressed and disabled following HCV infection and drug treatment. An improperly disposed needle stuck the health care worker when she picked up a trash bag in the emergency department of a South Carolina hospital in September 1996.
"Unfortunately, she seroconverted with [HCV] positivity at about 13 weeks," Ball said.
After developing acute HCV infection, the worker took interferon for five months, and her liver function tests returned to the normal range.
"Unfortunately, probably due to the interferon, she has become severely depressed and is now on two antidepressants with psychiatric help, and is not working," he said. The National Institutes of Health estimates that about 15% of interferon recipients experience severe depression, said Ball, adding that underlying psychiatric problems are a contraindication for the drug. Complicating the case, the former housekeeper also has developed a post-traumatic stress disorder related to the injury, he added. Medical costs, lost wages, and disability have come to $161,000 in the nearly two years since the injury, he noted. Additional costs in the $600,000 range are anticipated if the worker remains disabled, and liver transplant costs also would have to be covered should the HCV recur and worsen, he noted.
"Unfortunately, there is this mindset that because there is no pre-exposure or postexposure prophylaxis [and] treatment is iffy at best - with protection against chronic disease in up to only half of the cases with interferon - then why test for it?" Ball asked. "I think we would all agree that baseline and follow-up testing upon an exposure incident is the proper course of management, even though we don't also have good postexposure treatment or interventions."
In that regard, a survey recently conducted by Ball and colleagues in South Carolina yielded some encouraging and somewhat surprising findings. Of the 46 hospitals that responded, 39 (85%) of the hospitals reported policies in place for baseline HCV testing of workers after blood exposures. In addition, 42 (91%) reported that HCV testing was done on source patients after an exposure to a health care worker.
"That number frankly surprised us," he said. "We expected to have a lower percentage."
[Editor's note: The Department of Health and Human Services has a 24-hour national toll-free hotline to help clinicians counsel and treat health care workers with job-related exposure to bloodborne diseases and infections, including hepatitis and HIV. The National Clinicians' Post-Exposure Prophylaxis Hotline (PEPline) number is (888) 448-4911. In addition, the CDC hepatitis branch has implemented a toll-free number to allow access to information on viral hepatitis: (888) 4HEPCDC. Health professionals and consumers also can obtain information on hepatitis C by calling the NIH's National Digestive Diseases Information Clearinghouse at (301) 654-3810, or by visiting its Web site at http://www.niddk.gov.]