ESTIMATING THE NUMBER OF HIV TRANSMISSIONS THROUGH REUSED SYRINGES AND NEEDLES IN THE MBEYA REGION, TANZANIA

Objective: HIV infection attributable to medical injections is suspect ed to be low, although case-control studies have not provided definite results. This study aims to determine the number of HIV infections ca used by the reuse of syringes and needles in the Mbeya Region, Tanzani a. Methods: The direct identification or detection of HIV in syringes and needles under field conditions was not appropriate, therefore a su rrogate marker consisting of two components for possible HIV transmiss ion was used: insufficient sterilization, and blood remaining from a p revious patient. The assumption was that HIV infection can only occur if both markers are positive. Samples were collected in nine health-ca re facilities. All syringes and needles prepared for use in these faci lities were collected without prior notification. The samples were rin sed and the resulting fluid was cultured for bacteria. Traces of blood were detected by urine stick test for haemoglobin volumes >0.0015 mu l. Results: Bacterial contamination was found in 32.8% of the total 12 19 syringes and needles; 67% was caused by improper handling of the eq uipment after sterilization. Blood was detected in 12.5% of the sample s. In the following three sampling strata, both contamination criteria were positive either on the syringe or the needle: wards/outpatient d epartments (OPD), 1.39%; laboratories, 7.45%; expanded programme on im munization (EPI), <0.1%. We calculated that from 1.1 million patients injected in wards/OPD in any 1 year, fewer than 13 become infected, in laboratories fewer than 12 (160 000 blood-taking procedures), and les s than one child in the EPI (850 000 vaccinations). Conclusion: With a n established AIDS intervention programme supporting the health system , less than 0.4% of the total annual incidence of 4500-8500 is attribu table to medical injections in the Mbeya Region.