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USE OF ACUTE HEPATITIS SURVEILLANCE TO EVALUATE PROGRAM FOR VIRAL HEPATITIS PREVENTION AND CONTROL Central Asian Program, DIH, EPO, CDC
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Acute Hepatitis Incidence, Kyrgyzstan, 1990-2002
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Weaknesses of the Acute Hepatitis Surveillance Used before 2000 –Acute hepatitis case definition was not applied –Cases were not serologically tested for specific markers of acute hepatitis A,B,C and D –Epidemiological data collection procedure and analysis methodology were not standardized
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Sentinel Surveillance Introduction (goals) To provide reliable etiological diagnostics of acute viral hepatitis on bases of representative sample To define risk groups and risk factors for acute hepatitis To use surveillance data for design, monitoring and evaluation of programs for viral hepatitis control and prevention To provide database for epidemiological studies
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Sentinel Surveillance Introduction (stages 1) National Reference Laboratory was established; standard laboratory procedures and quality assurance were provided External Quality Assessment of the accuracy of Reference laboratory results was conducted in CDC, Atlanta Corresponding Ministry of Health orders were issued Sentinel Sites were organized in three regions: Bishkek, Naryn and Jalal-Abad
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Sentinel Surveillance Introduction (stages 2) The structure and procedure of sentinel surveillance were developed, including: –sample size and sampling design –acute hepatitis case definition –algorism of laboratory testing –acute hepatitis case classification –standard questionnaire for epidemiological data collection –blood samples collection and transportation 4 trainings have been conducted for the sentinel sites personnel (laboratory workers, physicians, epidemiologists, nurses) on sentinel surveillance structure and operating, data quality assurance
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Acute Hepatitis Case Infectious Hospital (physician, nurse) - confirmation of correspondence to case definition - filling in and marking of the questionnaire - blood sample collection and marking - transportation of samples and questionnaires to the State Sanitation and Epidemiological Surveillance Center State Sanitary and Epidemiological Surveillance Center (epidemiologist, laboratory worker) - serum separation - transportation of samples and questionnaires to the Reference Laboratory
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(epidemiologist, laboratory worker) - laboratory testing - data entering - data analysis and report preparation Ministry of Health State Department of Sanitation and Epidemiological Surveillance Regional health authorities and State Sanitation and Epidemiological Surveillance Centers report
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Algorithm of Laboratory Testing Blood sample HBsAg IgM anti-HBc IgM anti-HAV Total anti-HCV Anti-HDV +
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GNP/capita (USD) 1994-2000 Country/Years19942000 (estimate for 2002) GNP increase Kazakhstan721123070.6% Kyrgyzstan275.32864% Tajikistan159.1159,80.4% Turkmenistan517552,56.9% Uzbekistan255.4264,33.4% European Bank for Reconstruction and Development. Transition Report Update, May 2002.
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Aims: To evaluate parenteral hepatitis risk factors To assess an impact of universal newborn Hepatitis B immunization program
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Materials and Methods (1) Study design: matched case control study (1 case + 2 controls matched by age, sex and place of residence) Cases: acute hepatitis B, C and D cases (parenteral hepatitis), 2000-2003 Controls: acute hepatitis A cases, 2000-2003 N = 214 case-control sets EPI INFO matched case-control analysis followed by conditional logistic regression
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Risk Factors (6 months prior to the onset of disease) Blood transfusion Surgery Injections in hospital Injections in polyclinic Blood samples collection in polyclinic Visit to surgeon, dentist, urologist, gynecologist Blood donation Multiple sexual partners STD
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Risk Factors of Parenteral Hepatitis (monovariate analysis) Факторы рискаFrequency (N=642) ORConfidence interval СI 0.95 P value Cases Controls Blood transfusion 5.6%0.2%24.0 [3.1; 184.6]<0.001 Injections in hospital 5.6%0.9%7.67.6[2.1; 27.6]<0.001 Injections in policlinic 22.0%7.2%3.53.5[2.1; 5.8]<0.001 Surgeon 7.0%1.6%4.8[1.9; 12.6]<0.001 Multiple sexual partners 4.7%1.4%8.78.7[1.8; 41.9]<0.05
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Risk Factors of Parenteral Hepatitis(2) Risk factors βί OR=e Confidence interval СI 0.95 P value Blood transfusion 11.4 [ 1.3; 99.7 ] <0,05 Injections in hospital 3.2 [ 2.0; 5.9 ] <0,001 Injections in policlinic 5.7 [ 1.1; 15.9 ] <0,001 Surgeon 1.1 [ 0.2; 5.4 ] >0,05 Multiple sexual partners 5.2 [ 1.5; 17.6 ] <0,01
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Conclusion Risk of parenterally transmitted viral hepatitis remains significant in health facilities. The system of blood and injection safety should be improved The system of health communication and training to improve understanding of natural Hep B transmission mechanisms and prevention measures should be strengthened (+HIV)
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Hepatitis B Immunization Program in Kyrgyzstan Introduced in April 1999 High immunization coverage – > 95% 23 cases of acute HB among fully immunized children registered by routine surveillance
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Surveillance Routine (syndrome based) High sensitivity (95%) Low specificity (17%) Sentinel (laboratory based) Low sensitivity (7%) High specificity (87%)
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Materials and Methods (2) Comparison of acute hepatitis B incidence rates among vaccinated and unvaccinated children born in sentinel sites between 2000 and 2003 Analyses of acute hepatitis B incidence among children under 5 years of age in sentinel sites for the period 2000 to 2003 –Hepatitis B cases: acute hepatitis sentinel surveillance database –Vaccination status of acute hepatitis B cases: primary health facility immunization records –Number of children in age groups and vaccination status of non-infected children: official statistical data of the Ministry of Health
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Acute Hepatitis B Cases Among Children Under 4, Sentinel Surveillance, 2000-2003 Sentinel sites Number of children under 4 Children born after April 1999 C hildren fully immunized Bishkek 1540 Dzalal-Abad 3392 Naryn 510 Total: 53142
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Incidence rates among vaccinated and unvaccinated children, Bishkek, Naryn, Jalalabat, 2000-2003 Number of children born in 2000-200337 784 Number of fully vaccinated children37 112 Number unvaccinated children672 Number of acute HB cases among vaccinated children 2 Number of acute HB cases among unvaccinated children 12 Incidence rate among vaccinated children2.9 per 100,000 child- years Incidence rate among unvaccinated children760.0 per 100,000 child-years
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Acute Hepatitis Incidence Among children under 5, 2000-2003 47,4 18,8 7 5,1 26 46 66 86 0 5 10 15 20 25 30 35 40 45 50 2000200120022003 % 0 10 20 30 40 50 60 70 80 90 100 Morbidity ratio %000 VHB morbidity rateVHB immunization coverage
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Conclusions (1) AHSS allows effective MONITORING of immunization program in sentinel sites, providing the ability to: –carry out epidemiological investigation of every case of acute viral Hepatitis B –identify and quickly respond to immunization program errors
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Conclusions (2) KAHSS provides: the ability to EVALUATE the impact of an immunization program an advocacy tool to support the necessity of sustainable immunization programs
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Study Limitations Evaluation of risk factors: –Use of acute hepatitis A cases as controls; –Aggregation of acute hepatitis B, C and D cases into one group of parenteral hepatitis Evaluation of Immunization program: –Use of official statistical data to define the size of target age groups and vaccinated and unvaccinated children
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Acknowledgements The Ministry of Health of the Kyrgyz Republic Republican Center for Viral Hepatitis Prevention State Department of Sanitation and Epidemiological Surveillance Republican Center for Immunization
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