covid spike antibody test results range 250

Although global health authorities including the World Health Organization previously cautioned against using binding antibodies to assess immunologic protection, several large studies subsequently demonstrated that SARS-CoV-2 spike binding antibodies (hereafter S antibodies) largely track with protection against infection ( 5– 7). The direct use of binding antibodies to estimate immunologic protection is, therefore, attractive, at least for population-based studies, where the tolerance for imprecision may be higher than vaccine efficacy trials. Recent approaches have combined screening subsets of populations for neutralizing activity and applying machine learning methods to estimate population-level immunologic protection ( 8), but those approaches still require neutralization testing of a certain fraction of samples in addition to applying machine learning methods. Although neutralizing antibodies are the generally accepted standard correlate of protection against symptomatic infection ( 5– 7), measuring neutralizing activity is slow and resource intensive and therefore impractical for most population-based studies, particularly in low- and middle-income countries. This focus was largely because of an urgent need to understand population-level transmission and transmission risks, but it was also the result of limited understanding of what binding antibody levels mean for immunologic protection and whether quantification of binding antibodies translate into actionable or otherwise useful data. Many large national seroepidemiologic studies were conducted in the pre–COVID-19 vaccine era and before emerging variants of concern, focusing primarily on seroprevalence (i.e., the presence or absence of SARS-CoV-2 antibodies) but not antibody levels ( 1– 4). Most countries launched national COVID-19 vaccination campaigns during early 2021, but few studies have characterized population-level immunologic responses to SARS-CoV-2, and fewer have aimed to translate findings to immunologic protection. Given widespread unreported SARS-CoV-2 infections, variable immunologic response based on host immunogenicity, vaccine type, viral strain, timing and sequence of vaccine or viral exposure, and humoral waning, the global SARS-CoV-2 immune landscape is largely unknown. Combining serologic and virologic screening might enable monitoring of discrete population immunologic markers and their implications for emergent variant transmission.

Multivariable binomial odds ratios for acute infection were 0.55 (95% CI 0.40–0.74), 0.38 (95% CI 0.27–0.55), and 0.27 (95% CI 0.18–0.40) for the second, third, and fourth versus the first anti-spike quartile findings were similar by viral strain. Geometric mean spike antibody titers increased from 6.6 (95% CI 5.1–8.7) binding antibody units (BAU)/mL during March–June 2021 to 1,332 (95% CI 1,055–1,682) BAU/mL during May–August 2022.

We tested serum samples for spike antibodies and tested nasopharyngeal samples for acute SARS-CoV-2 infection using a reverse transcription PCR nucleic acid amplification test. To assess changes in SARS-CoV-2 spike binding antibody prevalence in the Dominican Republic and implications for immunologic protection against variants of concern, we prospectively enrolled 2,300 patients with undifferentiated febrile illnesses in a study during March 2021–August 2022. Kucharski) Yale School of Medicine, New Haven, Connecticut, USA (M. Lau) London School of Hygiene and Tropical Medicine, London, England, UK (A. Baez) University of Queensland, Brisbane, Queensland, Australia (C.L. Strobel) Dominican Republic Office of the Presidency, Santo Domingo (A.A. Then Paulino) Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas, USA (S.M. Zielinski Gutiérrez) Ministry of Health and Social Assistance, Santo Domingo (L. Duke) US Centers for Disease Control and Prevention, Central America Regional Office, Guatemala City, Guatemala (B. Jarolim) Pedro Henríquez Ureña National University, Santo Domingo, Dominican Republic (W. Durski) Harvard Medical School, Boston (E.J. Durski) Harvard Humanitarian Initiative, Cambridge, Massachusetts, USA (E.J. Author affiliations: Brigham and Women’s Hospital, Boston, Massachusetts, USA (E.J.

Covid spike antibody test results range 250