The Surprising Absence of Disease Transmission From Infection Control Disasters

by John Hardie BDS, MSc, PhD, FRCDC

From the mid- 1980s and throughout the early 1990s there was an explosion of infection control recommendations from dental regulatory agencies, national and provincial dental associations and various speciality disciplines. This excess had as its primary function the prevention of the transmission of HIV, hepatitis B and hepatitis C during the practice of dentistry. Following the adoption of these recommendations, it was no longer possible to test their efficacy since deliberately avoiding them, even in a controlled experiment, could be construed as malpractice.

In recent months, gross breaches of infection control in dental and medical offices have been reported in the media. Since it was believed that such infection control disasters could transmit the above diseases, patients of the involved practices were publicly advised to be tested for HIV, hepatitis B and hepatitis C. While it would be hoped that no such transmissions would occur, the test results are a means of assessing what occurs when mandated infection control procedures are not followed.

This article discusses the test results on patients treated with what were considered less than acceptable infection control protocols. The first set of results are from the patients of the Burnaby/Richmond based “rogue dentist,” the second set relates to the patients of a USA oral surgeon and the third concerns the patients of an Ottawa area physician.

The “Rogue Dentist”
As reported previously in Oral Health, the failure by Tung Sheng (David) Wu to adopt mandatory infection controls was deemed sufficient justification for the Fraser Health Authority and the College of Dental Surgeons of BC to recommend in August 2013 that approximately 1,500 of Wu’s patients be tested for HIV, hepatitis B and hepatitis C.1 As of mid-August 2013, the College of Dental Surgeons of BC was unaware of any serious medical conditions traceable to Wu’s practice.1

In August of 2014, the author attempted to determine the then current level of knowledge that the college might have relating to the results of the tests that it had advised. The response was confined to a narrow description of the college’s legal jurisdiction of the case but did include a helpful referral to the involved health authorities.

Michelle Murti, Medical Officer of the Fraser Health Authority, shared the following details. The authority tested approximately 400 of Wu’s patients. Not one of them had any evidence of HIV, hepatitis B or hepatitis C traceable to Wu’s lack of infection control.

Anecdotal reports suggest that Vancouver Coastal Health tested around 300 of Wu’s patients. One was positive for HIV. However, that individual was at high risk for HIV, ruling out Wu’s practice as the source of the infection.

It appears that despite a gross lack of infection controls, Wu’s dental activities were not transmitters of HIV, hepatitis B or hepatitis C.

The Oral Surgeon
On March 28th, 2013, Oklahoma public health officials closed Dr. Scott Harrington’s Tulsa based oral surgery practice and urged approximately 7,000 of his patients to be tested for HIV, hepatitis B and hepatitis C. The officials deemed the oral surgeon to be a “menace to the public health” following an inspection of his practice, which revealed multiple sterilization issues including improper use of sterilizers, possible cross-contamination by needles and potentially contaminated drug vials, the reuse of rusty instruments on multiple patients known to carry infectious diseases and the inappropriate administration of IV sedation by unlicensed assistants.2,3 According to Susan Rogers, Executive Director of the Oklahoma Board of Dentistry, Dr. Harrington’s practice, by failing to follow basic universal precautions for blood-borne pathogens, was a “perfect storm” for exposure to HIV and hepatitis infections. This was compounded by Dr. Harrington’s admission that he had a higher number than normal of HIV and hepatitis patients.3

The Oklahoma State Department of Health (OSDH) and the Tulsa Health Department conducted the epidemiologic investigations of the possible transmissions from Dr. Harrington’s practice. On the October 17th, 2013, the results of the investigations were announced by the OSDH.4 The Oklahoma Public Health Laboratory completed testing for 4,208 of Dr. Harrington’s patients. Four patients were positive for HIV, six for hepatitis B and 90 for hepatitis C.4 The numbers are not surprising considering Dr. Harrington’s admission that a high number of his patients were known to harbour such infections. What is interesting is that genetic testing failed to link any of the HIV or hepatitis B cases to transmissions occurring in Dr. Harrington’s practice.4 The only possible linkage was a single case of hepatitis C transmission among the 90 infected patients.4

To-date, this is the only case of hepatitis C transmission occurring in an oral surgery/dental practice. In consideration of this and the fact that many of Dr. Harrington’s patients had hepatitis C acquired from other sources, it is important to know why the linkage was seemingly established and subsequently widely reported in the lay press.5

Genotype refers to the genetic structure of living organisms. The hepatitis C virus (HCV) has at least six different genotypes. Approximately 75 percent of Americans with HCV have genotype 1 (subtype 1a or 1b), about 20-25 percent have genotypes 2 and 3, and a small number have genotypes 4, 5 or 6.6,7 HCV is constantly mutating both spontaneously and in reaction to immunologic responses. These further mutations are referred to as quasispecies.6,7 Genotypes represent major genetic differences and do not change with time. Whereas, quasispecies represent minor genetic differences that, over time, do evolve and change in an infected person.6,7,8 The process of constant mutation helps the virus escape the body’s immune defences, for as soon as the dominant quasispecies is immunologically destroyed, another variant emerges. This might be a reason why HCV commonly evolves into a chronic infection.8 Quasispecies analysis has been used to establish linkages in the transmission of HVC infection: between mother and infant; during anaesthesia; from contaminated equipment and from inappropriate infection control practices.9

A quasispecies analysis of HCV patients in Dr. Harrington’s practice revealed a maximum genetic similarity between a chronically infected patient and one who, following treatment, developed an acute hepatitis C infection.6 In support of the linkage was the fact that on July 17th, 2012, the patient with the subsequent acute hepatitis C infection was treated immediately following and in the same operatory as the chronically infected patient. Both patients received care under IV sedation.6

The above appears to be convincing proof of hepatitis C having been transmitted in Dr. Harrington’s practice, perhaps from the re-use of contaminated instruments or the sharing of needles or syringes.10 However, additional information clouds this conclusion.

Measurements of HCV quasispecies are mainly of research interest with little applicability to the management and treatment of hepatitis C infection.7 The quasispecies analysis on the two patients demonstrated a 100 percent similarity in a partial genomic region termed NS5.6 Bukh and colleagues have demonstrated that there are distinct shortcomings in the interpretation of results, which rely on analysing only limited gene regions.11 Many investigators believe there are literally millions of different quasispecies in everyone infected with hepatitis C.8 Therefore, since quasispecies are constantly mutating, the shari
ng of a particular gene region may simply represent a random occurrence which might be the situation with the supposed HCV transmission between Dr. Harrington’s patients.

Despite Dr. Harrington’s practice being an apparent ideal environment for the spread of infectious diseases, there is no evidence to support the transmission of HIV or hepatitis B. While laboratory results are suggestive of a hepatitis C transmission, definitive clinical evidence is lacking as supported by the State’s epidemiologist, who noted that the investigation “will not be able to determine exactly how the transmission occurred.”10

The Physician
In mid- 2011, Dr. C. Farazli, an Ottawa internist, was ordered by the Ontario College of Physicians and Surgeons to stop performing endoscopies due to issues relating to cross contamination, improper cleaning procedures, inadequate sterilization, poor record keeping and an abusive attitude towards her patients — a situation which had existed for almost ten years.12

Following these revelations and the closure of the clinic, Ottawa Public Health sent 6,800 letters to patients of the clinic warning them to be tested for HIV, hepatitis B and hepatitis C.13 This mass public notification cost $730,000 which, after a year-long investigation, failed to find any evidence of HIV, hepatitis or hepatitis C transmission being linked to Dr. Farazli’s practice.12,13

Commenting on the possibility that a clinic patient might have contracted hepatitis C, an Ottawa Public Health official stated that the probability of this occurring from improperly sterilized equipment is 1 in 50 million.14 Dr. Mark Tyndall of the Ottawa Hospital supported this contention noting that approximately one percent of the population has HCV antibodies. This would mean that among Dr. Farazli’s 6,800 patients about 68 would test positive for hepatitis C and make pinpointing the source of the infection a “real challenge”.14 These comments are pertinent to the HCV cases in Dr. Harrington’s practice.

According to the Ontario College, Dr. Farazli practiced for more than ten years with “a blatant disregard for the safety of your patients and ignorance of the fundamental principles of infection control”.13 Despite this strong condemnation, no evidence is available linking disease transmission to a lack of officially sanctioned infection control procedures.

These reports involve approximately 15,000 patients who were exposed to infection control disasters. The investigations of possible transmissions of serious blood-borne infections were carried out by experienced public health authorities. Although not all exposed patients were tested, the results among three different types of practices are remarkable for the consistent lack of transmission. Accordingly, it is reasonable to question to what degree official infection control recommendations are justified.

It is an incontestable fact that the approach to outpatient infection control since the mid-1980s has been driven by HIV/AIDS and to a lesser extent by concerns relating to hepatitis B and hepatitis C. In this context, it is relevant to note that prior to the adoption of currently recommended techniques, there was a remarkable paucity of documentation linking dental instruments and treatment to the spread of disease transmission, with no evidence that dentists had any greater experience of dying from infectious diseases than the general public.15,16

Subsequent to the appearance of HIV/AIDS, the foundations of dental infection control have been based on the precautionary principle. The precautionary principle has, as its basis, the idea that since it is better to be safe than sorry, preventive measures should be implemented prior to knowing whether they are either necessary or effective. The above results do question to what degree current infection control procedures prevent transmissions since their absence does not appear to have caused any infections.

The precautionary principle is often driven by fear resulting in irrational outcomes. Is it rational that an 80-year-old edentulous patient having impressions, a young teenager having orthodontic elastics adjusted and a known drug abuser undergoing a surgical extraction, are subjected to the same infection control protocols? This concept, readily embraced by regulatory agencies, was based on the 1993 edict that a universal infection control policy, which considers every patient as infectious – should be the norm in every dental office.17 This supposition is not only wrong, it is insulting to the majority of patients.

Current infection control is supposed to enhance the safety of patients and health care workers. Apart from the benefits of hepatitis B vaccine, what evidence exists proving that today’s dental operatory is any safer for patients and staff than it was in the 1960s? Regulatory agencies promote the idea that adoption of their regulations and recommendations will ensure safe, non-infectious dental practices. Such a level of certainty is impossible to guarantee, as no system is infallible.

Although a promoter of safety, the precautionary principle has harmful outcomes. Approved infection controls have never been subjected to cost-benefit analyses. It is simply not known to what extent their costs and time consumption have deprived the less fortunate from receiving essential treatment or influenced the implementation of care in developing countries. What environmental degradation has occurred due to the excessive use of rubber gloves, paper masks, strong disinfectants and potent chemicals?

The precautionary principle permitted the mandating of preventive measures with only a limited awareness of their effectiveness or of the infectious risks imposed by dental health practices.18 The weakness of this approach is revealed by the apparent absence of transmissions when the preventive measures are not enacted. This would indicate that less intensive infection control techniques would produce results similar to those currently imposed. The only losers of such an approach would be the manufacturers of the myriad of infection control paraphernalia saturating the market.

Perhaps, it is time to admit that the fear, uncertainty and hyperbole that surrounded HIV/AIDS forced authorities — with some justification — to overreact to perceived infectious disease risks associated with dental practice. Perhaps, it is also time to abandon the precautionary principle in favour of direct risk assessment by the attending dental practitioner. The knowledge that the treating dentist has of the principles of disease transmission and the patient’s health provide sufficient information to adopt infection control measures that are commensurate with the proposed treatment.

This suggestion has validity when the surprising result of this review is that the absence of officially sanctioned infection control recommendations does not result in the transmission of HIV/AIDS, hepatitis B and hepatitis C. OH

Dr. Hardie’s initial involvement with Evidence-Based Care was in 1996 while assisting the RCDSO in the development of Infection Control Recommendations. Subsequent experiences have tempered his enthusiasm for the concept.

Oral Health welcomes this original article.


1. Hardie J. The Rogue Dentist, Infection Control and Questionable Testing. Oral Health, Nov. 2013

2. Juozapavicius J. “Menace to the public health”: 7,000 dental patients urged to get HIV test after inspectors find filthy conditions. National Post, March 28th, 2013.

3. Castillo M. Dentist’s office a “perfect storm” for HIV, hepatitis exposure, healt
h official says. CNN Health, March 29th, 2013.

4. Oklahoma State Department of Health. Health Officials Announce New Results of Harrington Investigation. October 17th, 2013.

5. Tulsa oral surgeon “who used rusty instruments and reused needles” is responsible for nation’s first transmission of hepatitis C between patients at a dental office. Daily Mail, September 18th, 2013.

6. Personal Communications from Dr. K. Bradley, Oklahoma State Public Health Epidemiologist. December, 2015.

7. Hepatitis C Genotypes and Quasispecies. Hepatitis C Technical Advisory Group 2005.

8. HCV Genotype, Quasispecies and Subtype. HCSP Fact Sheet, Version 7, October 2014.

9. Panella H, et al. Transmission of Hepatitis C Virus during Computed Tomography Scanning with Contrast. Emerging Infectious Diseases 2008; 14(2): 333-336.

10. Hepatitis C Spread Between Patients At Dental Clinic For First Time: Oklahoma Health Officials. September, 18th 2013,

11. Bukh J et al. Genetic heterogeneity of hepatitis C virus: quasispecies and genotypes. Seminar Liver Dis. 1995; 15(1): 41-63.

12. Payne E. Doctor rebuked, will quit practice. Ottawa Citizen. July 25th, 2014.

13. Long J. Christiane Farazli’s endoscopy work called abusive, unconscionable. CBC News, July 24th, 2014.

14. Hep C patient feared Farazli endoscopy unsanitary. CBC News, November 17th, 2011.

15. Lewis DL et al. Cross-infection Risks Associated with Current Procedures for Using Highspeed Dental Handpieces. J Clin Microbiol. 1992; 30: 401-406.

16. Thomas LE et al. Survival of herpes simplex virus and other selected microorganisms on patient charts: potential source of infection. JADA. 1985; 111: 461-464.

17. Samaranayake L. Rules of infection control. Int Dent J. 1993; 43(6): 578-584.

18. CDC. Guidelines for Infection Control in Dental Health-Care Setting-2003. MMWR 2003/52(RR17): 1-61