Global seroprevalence of SARS-CoV-2 antibodies: a systematic review and meta-analysis

BackgroundMany studies report the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. We aimed to synthesize seroprevalence data to better estimate the level and distribution of SARS-CoV-2 infection, identify high-risk groups, and inform public health decision making. MethodsIn this systematic review and meta-analysis, we searched publication databases, preprint servers, and grey literature sources for seroepidemiological study reports, from January 1, 2020 to December 31, 2020. We included studies that reported a sample size, study date, location, and seroprevalence estimate. We corrected estimates for imperfect test accuracy with Bayesian measurement error models, conducted meta-analysis to identify demographic differences in the prevalence of SARS-CoV-2 antibodies, and meta-regression to identify study-level factors associated with seroprevalence. We compared region-specific seroprevalence data to confirmed cumulative incidence. PROSPERO: CRD42020183634. ResultsWe identified 968 seroprevalence studies including 9.3 million participants in 74 countries. There were 472 studies (49%) at low or moderate risk of bias. Seroprevalence was low in the general population (median 4.5%, IQR 2.4-8.4%); however, it varied widely in specific populations from low (0.6% perinatal) to high (59% persons in assisted living and long-term care facilities). Median seroprevalence also varied by Global Burden of Disease region, from 0.6 % in Southeast Asia, East Asia and Oceania to 19.5% in Sub-Saharan Africa (p<0.001). National studies had lower seroprevalence estimates than regional and local studies (p<0.001). Compared to Caucasian persons, Black persons (prevalence ratio [RR] 3.37, 95% CI 2.64-4.29), Asian persons (RR 2.47, 95% CI 1.96-3.11), Indigenous persons (RR 5.47, 95% CI 1.01-32.6), and multi-racial persons (RR 1.89, 95% CI 1.60-2.24) were more likely to be seropositive. Seroprevalence was higher among people ages 18-64 compared to 65 and over (RR 1.27, 95% CI 1.11-1.45). Health care workers in contact with infected persons had a 2.10 times (95% CI 1.28-3.44) higher risk compared to health care workers without known contact. There was no difference in seroprevalence between sex groups. Seroprevalence estimates from national studies were a median 18.1 times (IQR 5.9-38.7) higher than the corresponding SARS-CoV-2 cumulative incidence, but there was large variation between Global Burden of Disease regions from 6.7 in South Asia to 602.5 in Sub-Saharan Africa. Notable methodological limitations of serosurveys included absent reporting of test information, no statistical correction for demographics or test sensitivity and specificity, use of non-probability sampling and use of non-representative sample frames. DiscussionMost of the population remains susceptible to SARS-CoV-2 infection. Public health measures must be improved to protect disproportionately affected groups, including racial and ethnic minorities, until vaccine-derived herd immunity is achieved. Improvements in serosurvey design and reporting are needed for ongoing monitoring of infection prevalence and the pandemic response. FundingPublic Health Agency of Canada through the COVID-19 Immunity Task Force.

Beam characteristics of the first clinical 360° rotational single gantry room scanning pencil beam proton treatment system and comparisons against a multi-room system.

PURPOSE: The purpose of this study was to present the proton beam characteristics of the first clinical single-room ProBeam Compact™ proton therapy system (SRPT) and comparison against multi-room ProBeam™ system (MRPT). MATERIALS AND METHODS: A newly designed SRPT with proton beam energies ranging from 70 to 220 MeV was commissioned in late 2019. Integrated depth doses (IDDs) were scanned using 81.6 mm diameter Bragg peak chambers and normalized by outputs at 15 mm WET and 1.1 RBE offset, following the methodology of TRS 398. The in-air beam spot profiles were acquired by a planar scintillation device, respectively, at ISO, upper and down streams, fitted with single Gaussian distribution for beam modeling in Eclipse v15.6. The field size effect was adjusted for the best overall accuracy of clinically relevant field QAs. The halo effects at near surface were quantified by a pinpoint ionization chamber. Its major dosimetric characteristics were compared against MRPT comparable beam dataset. RESULTS: Contrast to MRPT, an increased proton straggling in the Bragg peak region was found with widened beam distal falloffs and elevated proximal transmission dose values. Integrated depth doses showed 0.105-0.221 MeV (energy sigma) or 0.30-0.94 mm broader Bragg peak widths (Rb80 -Ra80 ) for 130 MeV or higher energy beams and up to 0.48-0.79 mm extended distal falloffs (Rb20 -Rb80 ). Minor differences were identified in beam spot sizes, spot divergences, proton particles/MU, and field size output effects. High passing scores are reported for independent end-to-end dosimetry checks by IROC and for initial 108 field-specific QAs at 3%/3 mm Gamma index with fields regardless with or without range shifters. CONCLUSIONS: The author highlighted the dosimetry differences in IDDs mainly caused by the shortened beam transport system of SRPT, for which new acceptance criteria were adapted. This report offers a unique reference for future commissioning, beam modeling, planning, and analysis of QA and clinical studies.

Genital Sweet's Syndrome in a patient with Acute Myelogenous Leukemia.

A 71 year old male presented to the emergency room for evaluation of acute erythema, edema and pain of the penis and scrotum. There was initial concern for Fournier's gangrene, however labs were unremarkable and vital signs were stable. He did not improve with antibiotics. Biopsy results showed neutrophil infiltration consistent with Sweet's Syndrome. He was started on corticosteroids and discharged home in stable condition. In a hemodynamically stable patient not responding to antibiotic therapy, close observation is prudent until the tissue biopsy results.

Endoscopic Management of Penetrating Urethral Injury After an Animal Attack.

Background: Initial management of urethral injury remains controversial concerning the use of suprapubic urinary diversion and delayed repair, primary open realignment, and primary endoscopic realignment. To our knowledge, we present the first reported case of a penetrating urethral injury because of an animal attack, without concomitant extragenitourinary system involvement, managed entirely endoscopically. Case Presentation: This is a case of an 82-year-old male who presented to the emergency department after an attack by a semidomesticated deer. He presented with a penetrating scrotal injury and gross blood at the meatus. A retrograde urethrogram was performed that revealed a urethral injury. Surgical exploration revealed an isolated 3-cm urethral defect. It was managed with primary endoscopic placement of a urethral catheter and suprapubic tube. Conclusion: Although initial management of urethral injuries remains controversial, an isolated urethral injury after a penetrating trauma because of an animal attack may be safely and effectively managed by primary endoscopic realignment.

Why Desired Newborn Circumcisions Are Not Performed: A Survey.

OBJECTIVE: To identify why parents who want their child circumcised do not have them circumcised before the window for newborn circumcision (NBC) closes. We evaluate many patients in our pediatric urology clinic for circumcision in the operating room, which is associated with increased inconvenience, morbidity, and cost. METHODS: From 2010 to 2013 we surveyed 53 parents seeking NBC for their sons less than 1 month old. We surveyed a second group of 51 parents with sons between 1 month and 2 years old seeking operating room circumcision. Both groups were asked why NBC was not performed in the hospital. RESULTS: From the 104 parents surveyed, the primary reasons NBC was not performed in both groups were that the hospital did not offer or provide NBC (23% in the younger group and 20% in the older group) and that the provider who does NBC was not available or able prior to discharge (21% in the younger group and 20% in the older group). Ineffective communication delayed NBC in 26% of the younger group and 9% of the older group. Health problems delayed NBC in 8% of the younger group and 30% of the older group. NBC was only delayed due to parent indecision in 2% of responses in the younger group and 6% in the older group. CONCLUSION: Inadequate healthcare system preparation, resources, and communication are the primary reasons NBC is delayed. More work to streamline the process for desired NBC is needed.

Dosimetric and radiobiological comparison of CyberKnife M6™ InCise multileaf collimator over IRIS™ variable collimator in prostate stereotactic body radiation therapy.

The impetus behind our study was to establish a quantitative comparison between the IRIS collimator and the InCise multileaf collimator (MLC) (Accuray Inc. Synnyvale, CA) for prostate stereotactic body radiation therapy (SBRT). Treatment plans for ten prostate cancer patients were performed on MultiPlan™ 5.1.2 treatment planning system utilizing MLC and IRIS for 36.25 Gy in five fractions. To reduce the magnitude of variations between cases, the planning tumor volume (PTV) was defined and outlined for treating prostate gland only, assuming no seminal vesicle or ex-capsule involvement. Evaluation indices of each plan include PTV coverage, conformity index (CI), Paddick's new CI, homogeneity index, and gradient index. Organ at risk (OAR) dose sparing was analyzed by the bladder wall Dmax and V37Gy, rectum Dmax and V36Gy. The radiobiological response was evaluated by tumor control probability and normal tissue complication probability based on equivalent uniform dose. The dose delivery efficiency was evaluated on the basis of planned monitor units (MUs) and the reported treatment time per fraction. Statistical significance was tested using the Wilcoxon signed rank test. The studies indicated that CyberKnife M6™ IRIS and InCise™ MLC produce equivalent SBRT prostate treatment plans in terms of dosimetry, radiobiology, and OAR sparing, except that the MLC plans offer improvement of the dose fall-off gradient by 29% over IRIS. The main advantage of replacing the IRIS collimator with MLC is the improved efficiency, determined from the reduction of MUs by 42%, and a 36% faster delivery time.