Environmental Burden of Disease Series, No. 11 Sharps injuries Assessing the burden of disease from sharps injuries to health-care workers at national and local levels Elisabetta Rapiti Annette Prüss-Üstün Yvan Hutin Series Editors Annette Prüss-Üstün, Diarmid Campbell-Lendrum, Carlos Corvalán, Alistair Woodward A Microsoft Excel spreadsheet for calculating the estimates described in this document can be obtained from WHO/PHE. E-mail contact: [email protected] World Health Organization Protection of the Human Environment Geneva 2005 WHO Library Cataloguing-in-Publication Data Rapiti, Elisabetta. Sharps injuries : assessing the burden of disease from sharps injuries to health-care workers at national and local levels / Elisabetta Rapiti, Annette Prüss-Üstün, Yvan Hutin. (Environmental burden of disease series / series editors: Annette Prüss-Üstün ... [et al.] ; no. 11) 1.Needlestick injuries - complications 2.Wounds, Stab - complications 3.Blood- borne pathogens 4.Hepatitis B - etiology 5.Hepatitis C - etiology 6.HIV infections - etiology 7.Accidents, Occupational 8.Health personnel 9.Risk assessment - methods 10.Cost of illness I.Prüss-Üstün, Annette. II.Hutin, Yvan J. F. III.Title IV.Series ISBN 92 4 159232 X (NLM classification: WO 700) ISSN 1728-1652 Suggested citation Rapiti, E, Prüss-Üstün, A, Hutin, Y. Sharps injuries : assessing the burden of disease from sharps injuries to health-care workers at national and local levels. Geneva, World Health Organization, 2005. (WHO Environmental Burden of Disease Series, No. 11). © World Health Organization 2005 All rights reserved. Publications of the World Health Organization can be obtained from Marketing and Dissemination, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel: +41 22 791 2476; fax: +41 22 791 4857; email: [email protected]). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to Marketing and Dissemination, at the above address (fax: +41 22 791 4806; email: [email protected]). The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. The World Health Organization does not warrant that the information contained in this publication is complete and correct and shall not be liable for any damages incurred as a result of its use. The named authors alone are responsible for the views expressed in this publication. Printed by the WHO Document Production Services, Geneva, Switzerland. ii Sharps injuries Table of contents Preface ................................................................................................................................. v Affiliations and acknowledgements ............................................................................................. vi Summary .............................................................................................................................. viii 1. Introduction ............................................................................................................................ 1 2. Methodology .......................................................................................................................... 3 2.1 Summary................................................................................................................... 3 2.2 Parameters and methods ........................................................................................... 3 2.3 Main assumptions of the method .............................................................................. 7 3. Data requirements.................................................................................................................. 8 3.1 Size of the exposed population (N(HCW)) ................................................................... 8 3.2 Proportion of health-care workers and the general population immunized against HBV (pi) .................................................................................... 8 3.3 Rate of transmission of infections (pt) ...................................................................... 8 3.4 Prevalence of infection in patients (pv) and incidence of infection in the general population (Ib(GP) )......................................................................................... 9 3.5 Average number of sharps injuries per health-care worker per year (n)................. 12 4. Uncertainty analysis ............................................................................................................. 14 5. An example of how to calculate the burden of disease from sharps injuries ....................... 16 5.1 Calculating the proportion of the general population susceptible to infection (ps(GP))....................................................................................................... 17 5.2 Baseline incidence of infection in the susceptible proportion of the general population, Ibs(GP) ........................................................................................ 19 5.3 Calculating the proportion of health-care workers susceptible to infection, ps(HCW)...................................................................................................... 19 5.4 Baseline incidence of infection among health-care workers, Ib(HCW) ...................... 20 5.5 Baseline number of infections among health-care workers, Nb .............................. 21 5.6 Incidence of infection from sharps injuries in health-care workers, In(HCW) ...................................................................................................................... 21 5.7 Number of infections in health-care workers from sharps injuries, Nn................... 22 5.8 Fraction of infections attributable to sharps injuries in health-care workers.................................................................................................................... 22 6. Additional information on sharps injuries............................................................................ 24 7. Next steps............................................................................................................................. 27 References ............................................................................................................................... 29 Annex 1 Estimates of the global disease burden from sharps injuries to health- care workers for the year 2000 .............................................................................. 37 Annex 2 Aide-mémoire for health-care worker safety........................................................ 49 iii Sharps injuries List of tables Table 1 Prevalence of HBV, HCV and HIV in hospital patients and in the general population, selected studies ............................................................................... 10 Table 2 Estimates of the annual frequency of sharps injuries in USA health-care workers .............................................................................................................. 12 Table 3 Studies investigating the frequency of sharps injuries....................................... 13 Table 4 Example of data for calculating the disease burden attributable to sharps injuries in the age group 20−29 years................................................................ 16 Table 5 Estimating the proportion of the general population susceptible to HBV using catalytic modelling................................................................................... 18 Table 6 Frequency of procedure the health-care workers were using at the moment of percutaneous injury, selected countries......................................................... 25 Table 7 Estimates of the annual number of percutaneous injuries per health-care worker, by job category, selected countries....................................................... 26 Table A1 Subregional estimates of HBV, HCV and HIV prevalence, year 2000 ............. 38 Table A2 Subregional estimates of HBV, HCV and HIV incidence in the susceptible general population for the year 2000 .............................................. 39 Table A3 Estimates of the number of health-care workers in the 14 WHO subregions and the proportion that is male ........................................................ 40 Table A4 Annual incidence of sharps injuries in the 14 WHO subregions, and data sources ............................................................................................................... 41 Table A5 WHO subregional estimates of hepatitis B vaccine coverage among health-care workers............................................................................................ 42 Table A6 Infections attributable to sharps injuries among health-care workers in the 14 WHO subregions .........................................................................................