Application of SARS-CoV-2 Serology to Address Public Health Priorities.

Background: Antibodies against SARS-CoV-2 can be detected by various testing platforms, but a detailed understanding of assay performance is critical. Methods: We developed and validated a simple enzyme-linked immunosorbent assay (ELISA) to detect IgG binding to the receptor-binding domain (RBD) of SARS-CoV-2, which was then applied for surveillance. ELISA results were compared to a set of complimentary serologic assays using a large panel of clinical research samples. Results: The RBD ELISA exhibited robust performance in ROC curve analysis (AUC> 0.99; Se = 89%, Sp = 99.3%). Antibodies were detected in 23/353 (6.5%) healthcare workers, 6/9 RT-PCR-confirmed mild COVID-19 cases, and 0/30 non-COVID-19 cases from an ambulatory site. RBD ELISA showed a positive correlation with neutralizing activity (p = <0.0001, R2 = 0.26). Conclusions: We applied a validated SARS-CoV-2-specific IgG ELISA in multiple contexts and performed orthogonal testing on samples. This study demonstrates the utility of a simple serologic assay for detecting prior SARS-CoV-2 infection, particularly as a tool for efficiently testing large numbers of samples as in population surveillance. Our work also highlights that precise understanding of SARS-CoV-2 infection and immunity at the individual level, particularly with wide availability of vaccination, may be improved by orthogonal testing and/or more complex assays such as multiplex bead assays.

Rheumatic heart disease echocardiographic screening: approaching practical and affordable solutions.

Rheumatic heart disease (RHD) affects at least 32.9 million people worldwide and ranks as a leading cause of death and disability in low-income and middle-income countries (LMICs). Echocardiographic screening has been demonstrated to be a powerful tool for early RHD detection, and holds potential for global RHD control. However, national screening programmes have not emerged. Major barriers to implementation include the lack of human and financial resources in LMICs. Here, we focus on recent research advances that could make echocardiographic screening more practical and affordable, including handheld echocardiography devices, simplified screening protocols and task shifting of echocardiographic screening to non-experts. Additionally, we highlight some important remaining questions before echocardiographic screening can be widely recommended, including demonstration of cost-effectiveness, assessment of the impact of screening on children and communities, and determining the importance of latent RHD. While a single strategy for echocardiographic screening in all high-prevalence areas is unlikely, we believe recent advancements are bringing the public health community closer to developing sustainable programmes for echocardiographic screening.

Echocardiographic prevalence of rheumatic heart disease in Brazilian schoolchildren: Data from the PROVAR study.

BACKGROUND: Accurate estimates of Rheumatic Heart Disease (RHD) burden are needed to justify improved integration of RHD prevention and screening into the public health systems, but data from Latin America are still sparse. OBJECTIVE: To determine the prevalence of RHD among socioeconomically disadvantaged youth (5-18years) in Brazil and examine risk factors for the disease. METHODS: The PROVAR program utilizes non-expert screeners, telemedicine, and handheld and standard portable echocardiography to conduct echocardiographic screening in socioeconomically disadvantaged schools in Minas Gerais, Brazil. Cardiologists in the US and Brazil provide expert interpretation according to the 2012 World Heart Federation Guidelines. Here we report prevalence data from the first 14months of screening, and examine risk factors for RHD. RESULTS: 5996 students were screened across 21 schools. Median age was 11.9 [9.0/15.0] years, 59% females. RHD prevalence was 42/1000 (n=251): 37/1000 borderline (n=221) and 5/1000 definite (n=30). Pathologic mitral regurgitation was observed in 203 (80.9%), pathologic aortic regurgitation in 38 (15.1%), and mixed mitral/aortic valve disease in 10 (4.0%) children. Older children had higher prevalence (50/1000 vs. 28/1000, p<0.001), but no difference was observed between northern (lower resourced) and central areas (34/1000 vs. 44/1000, p=0.31). Females had higher prevalence (48/1000 vs. 35/1000, p=0.016). Age (OR=1.15, 95% CI:1.10-1.21, p<0.001) was the only variable independently associated with RHD findings. CONCLUSIONS: RHD continues to be an important and under recognized condition among socioeconomically disadvantaged Brazilian schoolchildren. Our data adds to the compelling case for renewed investment in RHD prevention and early detection in Latin America.