Nigeria - Nigeria HIV-AIDS Indicator and Impact Survey (NAIIS) 2018

During the household data collection, questionnaire and laboratory data were transmitted between tablets via Bluetooth connection. This facilitated synchronization of household rosters and ensured data collection for each participant followed the correct pathway. All field data collected in CSPro and the Laboratory Data Management System (LDMS) were transmitted to a central server using File Transfer Protocol Secure (FTPS) over a 4G or 3G telecommunication provider at least once a day. Questionnaire data cleaning was conducted using CSPro and SAS 9.4 (SAS Institute Inc., Cary, North Carolina, United States). Laboratory data were cleaned and merged with the final questionnaire database using unique specimen barcodes and study identification numbers.
All results presented in the technical report were based on weighted estimates unless otherwise stated. Analysis weights accounted for sample selection probabilities and adjusted for nonresponse and noncoverage. Nonresponse adjusted weights were calculated for households, individual interviews and individual blood draws in a hierarchical form. Adjustment for nonresponse for initial individual and bloodlevel
weights was based on the development of weighting adjustment cells defined by a combination of variables that were potential predictors of response and HIV status. The nonresponse adjustment cells were constructed using the Chi-square Automatic Interaction Detector (CHAID) algorithm. The cells were defined based on data from the household interview for the adjustment of individual-level weights and from both the household and individual interviews for the adjustment of blood specimen-level weights.
Post-stratification adjustments were implemented to compensate for non-coverage in the sampling process. This final adjustment calibrated the nonresponse-adjusted individual and blood weights to make the sum of each set of weights conform to national population totals by sex and five-year age groups.
Descriptive analyses of response rates, characteristics of respondents, HIV prevalence, CD4 count distribution, HIV testing, self-reported HIV status, self-reported ART, VLS, PMTCT indicators, HBV, HCV and
sexual behavior were conducted using SAS 9.4.

Data collection was done using CSPro verion 7.2 for CAPI Android.
Incidence estimates were based on the number of HIV infections identified as recent with the HIV-1 LAg Avidity plus VL algorithm and ARV algorithm and obtained using the formula recommended by the WHO
Incidence Working Group and Consortium for Evaluation and Performance of Incidence Assays and with assay performance characteristics of a mean duration of recent infection (MDRI) = 130 days (95% CI: 118,
142), a time cutoff (T) = 1.0 year and percentage false recent (PFR) = 0.00.