Background: South Africa implements variations of second generation suveilance\nsurveys to monitor human immunodeficiency virus (HIV) epidemic.\nObjective : This paper compares HIV estimates from two design variations:\ntake all approach and sub-sampling approach to ascertain if any changes in\nHIV epidemic are due to methodological changes or inherent evolution of the\nepidemic. Methods : A multi-stage stratified cluster sample of 1000 census\nenumerator areas was implemented with 15 households systematically sampled\nwithin each census enumerator area. In each household, every member\nwas invited to participate (take all approach). To compare to the previous\nsurvey designs, a sub-sampling approach of at most four people from each\nhousehold was implemented by randomly sampling one person from each\nage group: <2 years, 2 - 14 years, 15 to 24 years and 25 years and above. Results\n: HIV estimates were comparable with no systematic pattern. Prevalence\nestimates were slightly higher 12.2% [11.4% - 13.1%] in the take all compared\nto 11.6% [10.6% - 12.6%] in the sub-sampling approach. Estimates from\nsub-sampling approach were more variable. The design effects in the take all...............
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