Abstract
IntroductionRepeat positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) following COVID-19 initial viral clearance (re-positivity) poses a public health management challenge. The objective was to determine factors associated with neutralizing antibody (Nab) level and re-positivity among patients infected with a single strain SARS-CoV-2.MethodsDuring a single strain SARS-CoV-2 cluster in Beijing, China, longitudinal individual clinical, virological, and immunological data were collected from 368 infections from June 13 to September 22, 2020. Factors associated with Nab level and re-positivity were analyzed using generalized estimating equations.ResultsA total of 353 (96%) SARS-CoV-2 infections had demographic, clinical, and laboratory data available. Among the 353 infections, 55 (15.5%) were re-positive, and blood draws were taken from 346 individuals (98.0%) during hospitalization and/or during the follow-up period. Symptoms were milder for the second-time admission for the re-positives, although 36.4% of re-positives presented with radiographic appearance of pneumonia manifestation. Compared to non-re-positive patients, NAb titers were lower among re-positives; NAb was positively associated with clinical severity. Samples from the lower respiratory tract manifested higher viral load than that from the upper respiratory tract. Multivariable analysis showed re-positivity was positively associated with being female [odd ratio (OR)=1.7, 95% confidence interval (CI) 1.1–2.8] and being aged <18 years (OR=5.2, 95% CI 1.5–18.1); having initially asymptomatic infection (OR=13.7, 95% CI 1.6–116.3); and negatively associated with a higher NAb level (OR=0.9, 95% CI 0.5–1.7).ConclusionsNAb may be important for sustained viral clearance. Lower respiratory tract infection was associated with higher viral load among all infections when compared to upper respiratory tract infection. Continuous lower respiratory and intermittent upper respiratory viral shedding among COVID-19 infections may occur.
Highlights
Repeat positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) following COVID-19 initial viral clearance poses a public health management challenge
The initial wave of infection was followed by 56 consecutive days without any newly confirmed infections in Beijing; an infection confirmed on June 11, 2020 initiated the second wave of a COVID-19 outbreak [2]
All infections from the outbreak were directly or indirectly epidemiological linked to one market, the Xinfadi (XFD) wholesales market, from the same transmission chain and all caused by the B.1.1 strain [2]
Summary
Definitions and examination criteria Five clinical severity categories of SARS-CoV-2 infections were defined in China: asymptomatic, mild, moderate, severe, and critical. Asymptomatic infections were designated in individuals who had no symptom but tested positive for SARS-CoV-2 by nucleic acid tests. In China, any positive SARS-CoV-2 infection was required to be quarantined in a hospital, and the patient could be discharged only if two consecutive (>24 hours apart) nucleic acid tests with negative results had been observed. 1. Data source and ethics Deidentified data of the patients were extracted and collected from Ditan Hospital, an infectious-disease-oriented hospital in Beijing that managed the majority of SARS-CoV-2 infections in Beijing. 2. Neutralizing antibody (NAb) Repeated blood draws were collected during and/or after the hospitalization of the XFD outbreak infection cases in Ditan Hospital from June 25 to August 28, 2020. Generalized estimating equations (GEE) with assigned time groups were calculated to analyze potential factors associated with repeated measures of NAb and re-positivity of nucleic acid tests. Data analysis and visualization were conducted using Stata/IC (version 16.0, StataCorp, College Station, Texas)
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