c , on behalf on the NAIIS Study Group Background: HIV drug resistance (HIVDR) surveillance is an important tool to monitor threats to progress towards epidemic control. The characterization of HIVDR in Nigeria at the national level is needed to inform both clinical decisions and population-level HIV policy strategies. This study uses data obtained from the Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS) to describe the prevalence and distribution of HIVDR in Nigeria.Methods: NAIIS was a cross-sectional, population-based survey of households throughout Nigeria in 2018. NAIIS was designed to provide estimates of HIV prevalence and related health indicators from a nationally representative sample. The study population included participants aged 15-64 years who tested positive for HIV, had a viral load at least 1000 copies/ml, and had available HIV drug resistance genotypes. HIV isolates were genotyped to detect drug resistance mutations. Individual characteristics of study participants associated with HIVDR were identified using a weighted multivariable logistic regression model.Results: Of 1355 respondents with available HIV genotypes, 293 (19%) had evidence of drug-resistant mutations (DRMs) that conferred resistance to at least one antiretroviral drug. The majority of DRMs observed conferred resistance to NNRTIs (17.6%) and NRTIs (11.2%). HIVDR was associated with being ART-experienced, longer duration on ART, and lower CD4 þ count but not sociodemographic characteristics. Conclusion:The population level DRM prevalence in Nigeria was consistent with what would be expected in a mature HIV treatment landscape. The continued roll out of a

Objectives:Non-disclosure of positive HIV status in population-based surveys causes underestimation of national HIV diagnosis and biases inferences about engagement in the care continuum. This study investigated individual and household factors associated with HIV non-disclosure to survey interviewers in Nigeria.Design:Secondary analysis of a cross sectional population-based household HIV survey.Methods:We analyzed data from adults aged 15–64 years who tested positive for HIV and had antiretroviral drugs (ARVs) in their blood from a nationally representative HIV sero-survey conducted in Nigeria in 2018. We considered ARV use as a proxy for knowledge of HIV diagnosis; thus, respondents who self-reported to be unaware of their HIV status were classified as non-disclosers. We estimated the associations between non-disclosure and various sociodemographic, clinical, and household characteristics using weighted logistic regression.Results:Among 1266 respondents living with HIV who were taking ARVs, 503 (40%) did not disclose their HIV status to interviewers. In multivariable statistical analyses, the adjusted odds of non-disclosure were highest among respondents aged 15–24 years, those with less than a primary school education, and those who were the only person living with HIV in their household.Conclusions:Non-disclosure of positive HIV status to survey personnel is common among adults who are receiving treatment in Nigeria. These findings highlight the importance of validating self-reported HIV status in surveys using biomarkers of ARV use. Meanwhile, it is crucial to improve disclosure by strengthening interview procedures and tailoring strategies towards groups that are disproportionately likely to underreport HIV diagnoses.

OBJECTIVES/GOALS: Recent in vitro evidence suggests that diverse parasite protein families called RIFINs and STEVORs are displayed on the surface of infected red blood cells and may have a role in severe malaria, but they remain sparsely studied in natural infections. We measured the RNA expression of these antigens in Malian children with severe or mild malaria illness. METHODS/STUDY POPULATION: We collected blood samples from Malian children aged six months to five years, including 14 with cerebral malaria, 10 with severe malarial anemia, and demographic-matched controls with mild, uncomplicated malaria. We extracted total RNA from each patient and used a custom capture array to selectively enrich Plasmodium falciparum parasite RNA. We then performed Illumina next-generation RNA sequencing and reconstructed parasite transcriptomes using reference-free de novo assembly. We identified RNA encoding RIFINs and STEVORs using an in-house classifier, then measured the diversity and abundance of gene expression for each infection. Expression diversity was defined as the number of unique variants transcribed. Expression abundance was calculated as transcripts per million (TPM). RESULTS/ANTICIPATED RESULTS: Cerebral malaria cases, but not severe malarial anemia cases, had higher diversity and abundance of RIFIN expression compared to mild infections. Type A RIFINs predominated over Type B RIFINs, and the same two RIFINs were predominantly expressed in all disease phenotypes. We anticipate that predominantly expressed RIFINs share high sequence homology with variants previously shown to bind blood antigens or immune inhibitory receptors. STEVOR expression was also higher in cerebral malaria compared to mild malaria, but STEVOR transcripts were sparse overall. DISCUSSION/SIGNIFICANCE: Elevated RIFIN expression in cerebral malaria over mild malaria supports a role for these antigens in pathogenesis. Severe malarial anemia may progress through a different pathogenic mechanism. Predominantly expressed RIFIN variants may be promising targets for vaccines and therapeutics to protect children against cerebral malaria.