Antibody seroconversion in asymptomatic and symptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Chuanhao Jiang,Kui Xiao,Erik De Clercq,Weihong Zhu,Nuno Rodrigues Faria,Yang Wang,Shi Tai,Junmei Xu,Guangdi Li,Chuan Wen,Zhongbiao Jiang,Yali Wang,Lingjun Wen,Min Hu

doi:10.1002/cti2.1182

Abstract

ObjectivesAsymptomatic and symptomatic patients may transmit severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), but their clinical features and immune responses remain largely unclear. We aimed to characterise the clinical features and immune responses of asymptomatic and symptomatic patients infected with SARS‐CoV‐2.MethodsWe collected clinical, laboratory and epidemiological records of patients hospitalised in a coronavirus field hospital in Wuhan. We performed qualitative detection of anti‐SARS‐CoV‐2 immunoglobulin M (IgM) and immunoglobulin G (IgG) using archived blood samples.ResultsOf 214 patients with SARS‐CoV‐2, 26 (12%) were asymptomatic at hospital admission and during hospitalisation. Most asymptomatic patients were ≤ 60 years (96%) and females (65%) and had few comorbidities (< 16%). Serum levels of white and red blood cells were higher in asymptomatic than in symptomatic patients (P‐values < 0.05). During hospitalisation, IgG seroconversion was commonly observed in both asymptomatic and symptomatic patients (85% versus 94%, P‐value = 0.07); in contrast, IgM seroconversion was less common in asymptomatic than in symptomatic patients (31% versus 74%, P‐value < 0.001). The median time from the first virus‐positive screening to IgG or IgM seroconversion was significantly shorter in asymptomatic than in symptomatic patients (median: 7 versus 14 days, P‐value < 0.01). Furthermore, IgG/IgM seroconversion rates increased concomitantly with the clearance of SARS‐CoV‐2 in both asymptomatic and symptomatic patients. At the time of virus clearance, IgG/IgM titres and plasma neutralisation capacity were significantly lower in recovered asymptomatic than in recovered symptomatic patients (P‐values < 0.01).ConclusionAsymptomatic and symptomatic patients exhibited different kinetics of IgG/IgM responses to SARS‐CoV‐2. Asymptomatic patients may transmit SARS‐CoV‐2, highlighting the importance of early diagnosis and treatment.

Highlights

As of 28 August 2020, more than 24 million people have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and antiviral agents and vaccines are still under development.[1,2,3] many strategies have been proposed to control and treat symptomatic patients with COVID-19, early prevention of human-to-human transmission by asymptomatic patients remains a challenge
immunoglobulin G (IgG) seroconversion was commonly found in both asymptomatic and symptomatic patients (85% versus 94%, P-value = 0.07), whereas immunoglobulin M (IgM) seroconversion was less common in asymptomatic
Based on a cohort of 26 asymptomatic and 188 symptomatic patients in a coronavirus field hospital, our study revealed three major findings: (1) asymptomatic patients, mostly young females ≤ 60 years, were observed in approximately 12% of nonseverely ill patients infected with SARS-CoV-2; (2) >90% patients experienced IgM/IgG seroconversion at the time of virus clearance, whereas the median time from the first virus-positive screening to IgG/IgM seroconversion was significantly shorter in asymptomatic than in symptomatic patients; and (3) at the time of virus clearance, asymptomatic patients had lower IgG/IgM titres and plasma neutralisation capacity than symptomatic patients

Summary

Introduction

As of 28 August 2020, more than 24 million people have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and antiviral agents and vaccines are still under development.[1,2,3] many strategies have been proposed to control and treat symptomatic patients with COVID-19, early prevention of human-to-human transmission by asymptomatic patients remains a challenge. Asymptomatic patients carry SARS-CoV-2 with a strong transmission potential,[4] but they are not routinely tested, especially in resource-limited regions. Despite their importance in public health control, the serological and clinical features of asymptomatic carriers remain poorly understood

Objectives

Methods

Results

Discussion

Conclusion