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Canadian Journal of Infectious Diseases
Volume 4, Issue 1, Pages 47-51
Original Article

Estimation of the Secondary Attack Rate for Delta Hepatitis Coinfection among Injection Drug Users

Christiane Poulin, Theresa Gyorkos, and Lawrence Joseph

Field Epidemiology Program, Laboratory Centre for Disease Control, National Health and Welfare, Ottawa and Department of Epidemiology and Biostatistics, McGill University and Division of Clinical Epidemiology, Montreal General Hospital, Montreal, Quebec, Canada

Received 15 July 1991; Accepted 28 November 1991

Copyright © 1993 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The secondary attack rate for delta hepatitis coinfection was estimated among a cluster of injection drug users (IDUs). The infections occurred during an epidemic of hepatitis B in a rural area of Nova Scotia in 1988 and 1989. Six IDUs formed a cluster of delta hepatitis coinfections, representing the first reported outbreak of delta hepatitis in Canada. Contact-tracing was used to identify a cluster of 41 IDUs potentially exposed to delta hepatitis. The index case of delta hepatitis coinfection was presumed to have led to five secondary cases. The secondary attack rate was estimated to be 13.2% (95% confidence interval 0.044 to 0.281). The estimated secondary attack rate may be a useful predictor of disease due to delta hepatitis coinfection in similar IDU populations.