Environmental determinants of Kaposi's sarcoma-associated herpesvirus (KSHV) transmission in rural Uganda (ENDKU study): Contributions to research on KSHV infection and reactivation in African children; A longitudinal cohort study.

BACKGROUND: The Environmental Determinants of KSHV transmission in rural Uganda (ENDKU) study began enrollment in February 2020 with the purpose of defining the relationship between malaria, primarily caused by Plasmodium falciparum in sub-Saharan Africa, and KSHV susceptibility and reactivation. Uganda is an ideal study site, because both malaria and KSHV are endemic and widespread, even among young children. METHODS: ENDKU is a longitudinal cohort study of infants enrolled at six months of age and followed until three years of age. The main study, and one smaller sub-study, is nested within the General Population Cohort (GPC), a long-standing population cohort in rural Uganda. The ENDKU study was created to test the hypothesis that P. falciparum malaria increases an infant's susceptibility to KSHV infection. A sub-study to evaluate the effects of P. falciparum on KSHV reactivation involves an additional cohort of 5-10-year-old children with and without acute malaria who presented to the GPC study clinic. For each study, participants provided demographic and behavioral data through administered questionnaires and blood and saliva samples. RESULTS: Despite barriers presented by the COVID-19 pandemic, the study team was able to leverage the long-standing relationship of the UK Medical Research Council and the Uganda Virus Research Institute (MRC/UVRI) with the community, a strong commitment to research, and a multi-disciplinary team of experts to successfully implement the ENDKU study. CONCLUSION: The results of this multi-pronged approach will answer important questions about the etiology and transmission of KSHV in sub-Saharan Africa and the data and samples collected will be an important future resource for scientific research in the region.

Risk Factors of SARS-CoV-2 Antibodies in Arapahoe County First Responders-The COVID-19 Arapahoe SErosurveillance Study (CASES) Project.

OBJECTIVES: Define the seroprevalence and risk factors for SARS-CoV-2 antibodies in Arapahoe County, Colorado first responders (eg, law enforcement, human services, fire departments). METHODS: Two hundred sixty four first responders were enrolled June to July 2020. SARS-CoV-2 seropositivity was defined as detection of immunoglobulin G (IgG) antibodies to both spike receptor binding domain and nucleocapsid in venous blood by validated enzyme-linked immunosorbent assay. We compared risk factors for being seropositive versus seronegative. RESULTS: 4% (11/264) were SARS-CoV-2 seropositive. Seropositive participants were significantly more likely to have lung disease (% seropositive, % seronegative; P-value) (36%, 8%; P = 0.01), prior SARS-CoV-2/COVID-19 testing (36%, 8%; P ≤ 0.01), a prior positive result (18%, less than 1%), and to believe they previously had COVID-19 (64%, 15%; P < 0.01). Only 15% of those believing they had COVID-19 had anti-SARS-CoV-2 antibodies. CONCLUSIONS: Human services employees and individuals with lung disease are at SARS-CoV-2 exposure risk. Few individuals believed they had COVID-19 had prior exposure.

Development and Validation of a Multiplex Microsphere Immunoassay Using Dried Blood Spots for SARS-CoV-2 Seroprevalence: Application in First Responders in Colorado, USA.

Serological testing of large representative populations for antibodies to SARS-CoV-2 is needed to estimate seroprevalence, transmission dynamics, and the duration of antibody responses from natural infection and vaccination. In this study, a high-throughput SARS-CoV-2 multiplex microsphere immunoassay (MMIA) was developed for the receptor binding domain (RBD) and nucleocapsid (N) that was more sensitive than enzyme-linked immunosorbent assay (ELISA) (98% versus 87%). The MMIA was then applied and validated in 264 first responders in Colorado using serum and dried blood spot (DBS) eluates, compared to ELISA, and evaluated for neutralizing antibodies. Four percent (11/264) of first responders were seropositive in July to August 2020. Serum and DBS were highly correlated for anti-RBD and anti-N antibodies (R = 0.83, P < 0.0001 and R = 0.87, P < 0.0001, respectively) by MMIA. The MMIA accurately predicted SARS-CoV-2 neutralizing antibodies using DBS (R = 0.76, P = 0.037). On repeat antibody testing 3 months later, anti-RBD IgG decreased less rapidly than anti-N IgG measured by MMIA, with a median change in geometric median fluorescence intensity of 62% versus 79% (P < 0.01) for anti-RBD and anti-N IgG, respectively. This novel MMIA using DBS could be scalable for rapid and affordable SARS-CoV-2 serosurveillance in the United States and globally.