OCCUPATIONAL EXPOSURES TO HIV AMONG HEALTHCARE WORKERS IN CANADA McCarthy G. M.¹, Harris K. A.¹, John M. A.², Stitt L. W.¹ ¹Schulich School of Medicine & Dentistry, The University of Western Ontario; ²Clinical Microbiology, London Health Sciences Centre: London, Canada. RESULTS BACKGROUND Healthcare workers (HCWs) who are exposed to blood or other body fluids capable of transmitting bloodborne pathogens (BBPs) are vulnerable to infection. Despite continuing concerns about occupational transmission, there are limited data related to the frequency of occupational exposures to BBPs among HCWs in Canada. We have completed sequential surveys of over 22,000 HCWs in Canada investigating occupational exposures to BBPs. The results of these studies related to occupational exposures to HBV and HCV have been presented previously. This report focuses on occupational exposures to the human immunodeficiency virus (HIV). OBJECTIVES To estimate the proportion of dentists, surgeons, hygienists in Canada and nurses in Ontario who report occupational exposures to HIV. DISCUSSION The risk of acquiring HIV infection after exposure to HIV as a result of a percutaneous injury or mucous membrane exposure has been estimated as 0.3% and 0.1% respectively. These risks can be reduced further by the use of appropriate post-exposure prophylaxis. In addition, many patients are being treated with HAART, which can reduce the virus level and infectivity of blood for prolonged periods. In April 2006, Health Canada published cumulative reports of eight HCWs with occupationally-acquired AIDS. The results of these studies indicate that the reported rates of occupational exposure to HIV among HCWs in Canada are low. However, it is likely that these results underestimate exposures to HIV because of reluctance to report exposures and the frequent uncertainty about the serostatus of the source patient. This was confirmed by investigations of non-response bias. Assuming an infectivity of 0.3 per exposure, estimates from the nurses’ study indicate that many nurses have been infected with HIV – partly because of their large numbers. To further investigate the discrepancy between published reports of occupationally- acquired HIV and estimates from nurses’ self reports, data was obtained from the Workers Compensation Board of Canada (WCBC) This data showed that 209 registered nurses had been compensated for time lost as a result of occupationally- acquired HIV during the 7 years 1998-2004. Prior to 1998 infections were not specified in WCBC data. CONCLUSIONS We do not know how many HCWs have occupationally-acquired HIV in Canada and elsewhere. Published reports of cases of documented or possible occupationally-acquired HIV greatly under-estimate the number of infected HCWs – especially nurses. Occupationally-acquired HIV is a tragedy for many HCWs and fear of infection is a major factor in HCWs’ reluctance to treat patients with HIV and other serious infections. RECOMMENDATIONS Interventions are required: To reduce exposures to HIV. To improve compliance with standard precautions and occupational health. To improve reporting of exposures Further research is required: To provide updated information for all groups of HCWs. To improve surveillance estimates of occupationally-acquired HIV. PERCENTAGE OF HCWs REPORTING OCCUPATIONAL EXPOSURES TO HIV In last year Ever Dentists 0.5 - Surgeons 0.9 - Hygienists 0.4 1.7 Nurses - 8.2 MEAN EXPOSURES TO BLOOD REPORTED BY HCWS IN THE LAST YEAR Percutaneous Mucous membrane Dentists 3 .0 1.5 Surgeons 4.5 2.2 Hygienists 4.8 1.2 Nurses 0.6 0.2 METHODS Mailed confidential surveys of stratified random samples of groups of HCWs: n N Dentists 6,440 15, 230 Surgeons 4,000 7, 680 Nurses* 5,810 89,300 Hygienists 5,900 15,380 *HCWs who had patient contact in the last three months were eligible. INSTRUMENTS: Questionnaires were developed and tested using focus groups, pilot studies and test-retest procedures. SURVEY ADMINISTRATION: Confidential mailed questionnaires with ID numbers with two additional mailings to non-respondents. Based on Dillman’s Total Design Method for mailed surveys. STATISTICAL ANALYSIS: Data were weighted to allow for different probability of selection and non - response among the strata. Descriptive statistics were obtained using SPSS/PC+ RESPONSE RATES % Dentists 66 Hygienists 56 Surgeons 56 Nurses 60 (adjusted for non-delivery) Other percutaneous injuries include kwire, sutures, cuts, bites, puncture wounds, solid trochar and wire injuries Other exposures include cautery burns, aerosolized vapour and non-blood fluid splashes Acknowledgements This study was supported by: Health Canada, Medical Research Council of Canada The Canadian Institutes of Health Research Dr Gillian McCarthy was Career Scientist, Ontario Ministry of Health, Health Research Personnel Development Program XVI INTERNATIONAL AIDS CONFERENCE, AUGUST 13 - 18 2006, TORONTO, CANADA