The bottom of the iceberg: Is there a hidden hepatitis epidemic beneath all of the outpatient outbreaks?

'Our concern is that this could represent the tip of an iceberg.'

Julie Gerberding, MD, MPH, former CDC director, reacting to a hepatitis outbreak in a clinic in Las Vegas.

Evelyn McKnightOnce thought of as shocking outliers, the continuing hepatitis outbreaks in ambulatory care settings and clinics increasingly suggest that for every cluster detected, many more infections acquired in health care are being missed due to inadequate surveillance systems and lack of public health resources to investigate individual cases.

These infections may be counted among hepatitis cases of unknown origin, but they are not being traced back to transmission in health care settings. For example, the Centers for Disease Control and Prevention reports that in 2006, national viral hepatitis surveillance data revealed that 50% of patients with acute hepatitis C virus (HCV) and hepatitis B virus (HBV) were reported without accompanying risk factor data.1 Among patients for whom risk factor data were reported, 56% with acute HBV infection and 32% with acute HCV infection could not specify a known risk factor for their infection (such as injection drug use, sexual or household contact with another infected person, occupational exposure to blood, or needlestick injury.) How many of them were infected in a health care setting? The honest answer: No one knows.

"Even if it is, say, 5% or 10%, the denominator is in the thousands of patients," says Joseph Perz, PhD, acting team leader for prevention in the CDC's division of health care quality promotion. "Our concern in this area has been increasing. Increased awareness to the possibility of health care transmission in itself has resulted in more reports coming in to CDC. So, if health departments had the resources to really dig into some of these cases — to investigate the lack of traditional risk factors — it is quite likely [they would find] more health care-associated transmission."

A CDC review of outbreak information revealed 33 outbreaks in nonhospital health care settings in the past decade, including 12 in outpatient clinics, six in hemodialysis centers, and 15 in long-term care facilities, resulting in 448 people acquiring HBV or HCV infection.2 Indeed, the situation in long-term care has the CDC considering whether to recommend universal HBV vaccination for nursing home residents.

"Through our review, we were fairly easily able to identify these 33 outbreaks and nearly 450 people who were infected as a result of the receipt of their health care," Nicole Thompson, PhD, MS, lead author of the CDC study and an epidemiologist in the division of viral hepatitis, told Hospital Infection Control & Prevention. "But in our hepatitis surveillance, there are many reported cases with no obvious risk factors. It's possible and likely that there are a number of people who acquired their infection as a result of health care."

A comprehensive approach involving better viral hepatitis surveillance and case investigation, health care provider education and training, professional oversight, licensing, and public awareness is needed to ensure that patients always are afforded basic levels of protection against viral hepatitis transmission, the CDC recommends.

"Part of this is a resource issue," Thompson says. "It is extremely resource-intense — in finance and personnel — to conduct investigations of a single case. Many of these health departments simply don't have the money to be able to conduct these investigations thoroughly."

Call for infection prevention training

In each of those outbreaks, the route of infection was patient-to-patient transmission due to failure of health care personnel to adhere to fundamental principles of infection control and aseptic technique (for example, reuse of syringes or lancing devices), the CDC found. The general consensus is that the outbreaks reflect less greed and evil than simple ignorance, with basic needle safety practice with syringes and vials repeatedly violated.

"I actually believe, in most cases, they really don't know or understand — it is extremely concerning," says Marion Kainer, MD, MPH, FRACP, medical epidemiologist and director of the hospital infections and antimicrobial resistance program at the Tennessee Department of Health in Nashville. "I really would like everybody who touches a patient in a health care setting to be required to have attended some very basic infection control course and have their basic competency tested so we know they understand this," she says.

Until that happens, such outbreaks are likely to continue, but they almost certainly will not all be detected. In particular, surveillance for hepatitis C virus is so problematic that clusters of patients — let alone individual cases — acquired in ambulatory care settings may be unrecognized. With an estimated 3.2 million chronically infected people nationwide, HCV infection is the most common bloodborne infection in the United States.

"There is a good chance that we may be missing clusters, specifically of hepatitis C," Kainer says. "If you look at the outbreaks in ambulatory/surgery centers that have been identified, in many cases, it was an astute clinician who actually recognized, [for example,] that they had two patients with a rare genotype and both had had medical procedures. I am personally concerned that we are missing cases of nosocomial transmission."

Case identification is difficult, because simple lab tests do not reveal if the HCV case is of recent acquisition or represents longstanding, chronic disease. "There is no laboratory test that can tell whether hepatitis C is acute or chronic, she says. "You cannot tell on the actual laboratory result. What is problematic is that many physicians rely on laboratory results — they do not actually contact the health department with acute cases of HCV. They assume that the lab has taken care of it. The volume that we get of hepatitis C antibody tests is so high that it is physically impossible for us with the resources that we have to follow up on every single one of those to determine whether it is acute or chronic. We get like 50,000 to 70,000 electronic lab reports of that per year."

As a result, Kainer is urging physicians, infection preventionists, and other clinicians in her state to alert the health department about any suspected acute HCV case, particularly if it may be linked to a health care setting.

"I told them that if you suspect that this is potential nosocomial transmission, make sure you note that and let the health department staff know it," she says. " And if you don't feel you are getting listened to, make sure that you contact me. That is what I have done, but I am still concerned that we may be missing cases specifically of acute HCV."

Surveillance varies across states

It doesn't get any easier to identify nosocomial cases once they have been reported and put into the various surveillance groups. For example, after asymptomatic infection and underreporting were taken into account, approximately 19,000 new HCV infections occurred in 2006, the CDC estimates. Of the cases reported in 2006 for which information concerning exposures during the incubation period was available, the most common risk factor identified was intravenous drug use (54%). However, recent surgery was reported by 16% of patients, suggesting that transmission could have occurred through health care contact. By combining those patients with those infected during health care but included among those with no reported risk factors, one could argue that a substantial number of health care infections are occurring. However, this requires conjecture and extrapolation beyond the limited data, which are gathered in surveillance systems that may vary in definitions and intensity from state to state.

"I can tell you that nationally, [hepatitis] surveillance is all over the board," says Elena M. Rocchio, MA, viral hepatitis surveillance coordinator in the New York State Department of Health in Albany. "As far as health care as a risk factor — we do look for that. Because here in New York, we have had our share of experience with health care-acquired hepatitis, so it has become a very standard question."

Indeed, the department recently announced an investigation and look-back notification study after a patient was infected with HCV while undergoing dialysis treatment in New York City. Health officials confirmed that one patient contracted HCV after undergoing dialysis at the Upper Manhattan Dialysis Center of Beth Israel Medical Center. Approximately 170 patients have been notified that they may have been exposed to hepatitis C and other bloodborne viruses while being treated at the facility. The hospital declined comment when contacted by HIC. The investigation is ongoing, but Rocchio says "there were a number of things that could have led to transmission in this case."

Given the concerns about testing and underreporting, the question remains how many such cases nationally may be occurring in ambulatory care without being investigated.

"That's a great question," Rocchio says. "We really don't have an idea. We don't have a baseline to work from. It may seem like we are finding more, but it may be that we have become attuned to it. I think it has probably been happening for quite some time and surveillance systems for hepatitis are relatively new. It has a lot to do with the shift of health care into office-based settings as well. You don't have the traditional infection control oversight in a private physician office that you do in a hospital. That may be leading to more transmissions, but that's all anecdotal."

Nevertheless, the outbreaks are all the more disturbing because more patients are seeking treatment in ambulatory care. The CDC recently reported that the number of outpatient surgery visits in the United States increased from 20.8 million visits in 1996 to 34.7 million visits in 2006. Outpatient surgery visits accounted for about half of all surgery visits in 1996 but nearly two thirds of all surgery visits in 2006, the report said. The "National Survey of Ambulatory Surgery" includes surgery visits by children and adults and procedures performed in both hospital-based and freestanding surgery centers.3 The procedures are certainly not becoming less invasive, but the patients keep on coming as a massive demographic change continues in health care delivery.

People, not numbers

Among such patients was Evelyn McKnight, who thought breast cancer was her biggest worry when she sought treatment in an outpatient oncology center in Fremont, NE, in 2000.

"The nurse accessed our ports with a new needle and a new syringe to draw blood," she tells HIC. "She then put the blood in lab collection vials, she took off the needle, but used that same syringe to access a 500 cc saline bag. She drew off 10 cc saline to flush our ports, but in [doing so] contaminated that whole saline bag. In the morning, the saline bag was clear, but by the afternoon, it was cloudy pink with bits of sediment in it. A patient with known hepatitis C genotype 3A came to the clinic in March of 2000 for treatment, and 99 of us contracted the virus from that index patient."

Though the case count may eventually be surpassed by the HCV outbreak in Las Vegas — more than 50,000 people have been urged to be tested — the Nebraska outbreak was considered a "never event" and still remains the largest single-source outbreak of HCV in U.S. history. However, as infection preventionists know all too well, the outbreaks continue, with other patients such as McKnight receiving letters advising them that they may have been exposed to bloodborne viruses at a clinic. She now lives with HCV.

"At this time, I am pretty stable —I am very fortunate," she says. "It has caused me to lead a more healthy lifestyle. I always tried to be healthy, but I am very careful not to drink [alcohol], no fatty foods and foods that are high in iron because the liver has trouble metabolizing iron-rich foods. I'm careful to get moderate exercise as best I can and avoid stress however I can. I did do six months of ribavirin interferon [treatment] in 2004, but unfortunately, it was not successful. So I'm kind of on a day-by-day journey here."

Turning her personal tragedy into a national movement, McKnight founded the patient advocacy group HONOReform. She is gathering allies in a national effort to change the system through education and legislation. As undefined as it is, the largely hidden epidemic of hepatitis in ambulatory care has a human face in McKnight and other patients like her, even those who received those traumatizing notification letters but fortunately tested negative.

"It really shakes one's confidence in the health care system," she says. "It's really a deep loss — a sense of betrayal and disillusionment. Because of the collective suffering [of all exposed patients], I am confident that there will be sweeping improvement in infection control in the United States. That's the solace that I take."


  1. Centers for Disease Control and Prevention. Surveillance for acute viral hepatitis—United States, 2006. MMWR Surveill Summ 2008; 57:1-24.
  2. Thompson ND, Perz JF, Moorman AC, et al. Nonhospital Health Care-Associated Hepatitis B and C Virus Transmission: United States, 1998-2008. Ann Intern Med 2009; 150: 33-39.
  3. Cullen KA, Hall MJ, Golosinskiy A. CDC Division of Healthcare Statistics. Ambulatory Surgery in the United States, 2006. 2009; 11:1-26.