A Dengue Sero-prevalence Study in the Metropolitan Area of Buenos Aires

A two-stage stratified design will be used. The primary sampling units will be mostly defined as the census sections of the 2010 National Census of Population, Households and Dwellings. It has 5 strata, constructed through a functional relationship between the income quintiles obtained in the Annual Household Survey (AHS) and the variables that were surveyed in the census. Stratum 1 corresponds to the lowest income population, while stratum 5 corresponds to the highest. The first stage of sampling in this framework will consist of about 100 to 300 primary sampling units, called primary units areas, selected with a probability proportional to size, the measure of size being the total number of dwellings.

A sample of 1,487 dwellings is proposed. In each primary unit area, a number of dwellings will be selected to be visited by enumerators, who will make a list of all members residing in the dwelling (regardless of whether they are from the same household) and select a member aged ≥18 years to proceed with the survey. This last selection is a 3rd and final sampling stage that will define the sample of 1487 participants to be tested. The sample size was calculated based on the estimated probability of pre-infection for each of the municipalities and localities participating in the survey.