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Antibody Formation

Antibody Response Following SARS-CoV-2 Infection and Implications for Immunity: A Rapid Living Review

Author/s: 
Mackey, K., Arkhipova-Jenkins, I., Armstrong, C., Gean, E., Anderson, J., Paynter, R. A., Helfand, M.

The aims of this rapid systematic review are to synthesize evidence on the prevalence, levels, and durability of the antibody response to SARS-CoV-2 infection among adults and how antibodies correlate with protective immunity. Given the rapidly evolving evidence within this field, the Agency for Healthcare Research and Quality’s Evidence-based Practice Center (AHRQ EPC) Program will maintain this report as a living review with planned ongoing literature surveillance and critical appraisal. We will provide regular report updates as additional evidence becomes available, modifying the scope of the review as new directions in SARS-CoV-2 immunity research emerge. This review was conducted in coordination with the American College of Physicians (ACP) as part of AHRQ’s standing work to provide health professional organizations and systems with evidence reviews to support the development of clinical guidance for their clinician members.

Keywords 
Health Services Research physicians Societies United States Immunity

Kinetics of viral clearance and antibody production across age groups in SARS-CoV-2 infected children

Author/s: 
Bahar, Burak, Jacquot, Cyril, Mo, Yunchuan D., DeBiasi, Roberta L., Campos, Joseph, Delaney, Meghan

Abstract

Objectives: To improve understanding of transition from viral infection to viral clearance, and antibody response in pediatric patients with SARS-CoV-2 infection.

Study design: This retrospective analysis of children tested for SARS-CoV-2 by RT-PCR and IgG antibody at a quaternary-care, free-standing pediatric hospital between March 13, 2020 to June 21, 2020 included 6369 patients who underwent PCR testing and 215 patients who underwent antibody testing. During the initial study period, testing focused primarily on symptomatic children; the later study period included asymptomatic patients who underwent testing as preadmission or preprocedural screening. We report the proportion of positive and negative tests, time to viral clearance, and time to seropositivity.

Results: The rate of positivity varied over time due to viral circulation in the community and transition from targeted testing of symptomatic patients to more universal screening of hospitalized patients. Median duration of viral shedding (RT-PCR positivity) was 19.5 days and time from RT-PCR positivity to negativity was 25 days. Of note, patients aged 6 through 15 years demonstrated a longer time of RT-PCR positivity to negativity, compared with patients aged 16 through 22 years (median=32 versus 18 days, P = .015). Median time to seropositivity, by chemiluminescent testing, from RT-PCR positivity was 18 days while median time to reach adequate levels of neutralizing antibodies (defined as comparable to 160 titer by plaque reduction neutralization testing) was 36 days.

Conclusions: The majority of patients demonstrated a prolonged period of viral shedding after infection with SARS CoV-2. It is unknown whether this correlates with persistent infectivity. Only 17 of 33 patients demonstrated adequate neutralizing antibodies during the timeframe of specimen collection. It remains unknown if IgG antibody against spike structured proteins correlates with immunity, and how long antibodies and potential protection persist.

Copyright © 2020. Published by Elsevier Inc.

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