ABSTRACT
Given the limited availability of serological testing to date, the seroprevalence of SARS-CoV-2-specific antibodies in different populations has remained unclear. Here, we report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seroreactivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors in early April 2020. We additionally describe the longitudinal dynamics of immunoglobulin-G (IgG), immunoglobulin-M (IgM), and in vitro neutralizing antibody titers in COVID-19 patients. The median time to seroconversion ranged from 10.3-11.0 days for these 3 assays. Neutralizing antibodies rose in tandem with immunoglobulin titers following symptom onset, and positive percent agreement between detection of IgG and neutralizing titers was >93%. These findings emphasize the importance of using highly accurate tests for surveillance studies in low-prevalence populations, and provide evidence that seroreactivity using SARS-CoV-2 anti-nucleocapsid protein IgG and anti-spike IgM assays are generally predictive of in vitro neutralizing capacity.
Subject(s)
Antibodies, Neutralizing/blood , Betacoronavirus/immunology , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Antibodies, Viral/immunology , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/immunology , SARS-CoV-2 , San Francisco/epidemiology , Sensitivity and Specificity , Seroepidemiologic Studies , Serologic Tests/methodsABSTRACT
We report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seropositivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors. We additionally describe the longitudinal dynamics of immunoglobulin-G, immunoglobulin-M, and in vitro neutralizing antibody titers in COVID-19 patients. Neutralizing antibodies rise in tandem with immunoglobulin levels following symptom onset, exhibiting median time to seroconversion within one day of each other, and there is >93% positive percent agreement between detection of immunoglobulin-G and neutralizing titers.
ABSTRACT
OBJECTIVE: To describe and evaluate the impact of quality improvement (QI) support provided to skilled nursing facilities (SNFs) by a Quality Improvement Organization (QIO). DESIGN: Retrospective, mixed-method, process evaluation of a QI project intended to decrease preventable hospital readmissions from SNFs. SETTING: Five SNFs in Connecticut. PARTICIPANTS: SNF Administrators, Directors of Nursing, Assistant Directors of Nursing, Admissions Coordinators, Registered Nurses, Certified Nursing Assistants, Receptionists, QIO Quality Improvement Consultant. INTERVENTION: QIO staff provided training and technical assistance to SNF administrative and clinical staff to establish or enhance QI infrastructure and implement an established set of QI tools [Interventions to Reduce Acute Care Transfers (INTERACT) tools]. MEASUREMENTS: Baseline SNF demographic, staffing, and hospital readmission data; baseline and follow-up SNF QI structure (QI Committee), processes (general and use of INTERACT tools), and outcome (30-day all-cause hospital readmission rates); details of QIO-provided training and technical assistance; QIO-perceived barriers to quality improvement; SNF leadership-perceived barriers, accomplishments, and suggestions for improvement of QIO support. RESULTS: Success occurred in establishing QI Committees and targeting preventable hospital readmissions, as well as implementing INTERACT tools in all SNFs; however, hospital readmission rates decreased in only 2 facilities. QIO staff and SNF leaders noted the ongoing challenge of engaging already busy SNF staff and leadership in QI activities. SNF leaders reported that they appreciated the training and technical assistance that their institutions received, although most noted that additional support was needed to bring about improvement in readmission rates. CONCLUSION: This process evaluation documented mixed clinical results but successfully identified opportunities to improve recruitment of and provision of technical support to participating SNFs. Recommendations are offered for others who wish to conduct similar projects.
