Original Article
A preliminary investigation on the serological and epidemiological characteristics of severe acute respiratory syndrome in children
CAO Li, WANG Tian-you, CHEN Hui-zhong, QIAN Yuan, CHEN Bo-wen, FANG Ping, SUN Yan-xiang, ZHU Ru-nan, DENG Jie, ZHAO Lin-qing, MI Jie, ZHANG Ting
Published 2004-11-16
Cite as Chin J Pediatr, 2004, 42(11): 840-844. DOI: 10.3760/cma.j.issn.0578-1310.2004.11.115
Abstract
ObjectiveThe severe acute respiratory syndrome (SARS) is a highly contagious infection caused by a newly discovered strain of coronavirus (SARS-CoV). During the outbreak of SARS in the first half of 2003, children appeared to be less susceptible to the SARS coronavirus and pediatric patients presented with a less aggressive clinical course than adult patients did, demonstrating the traits which were rarely observed in other viral contagious disease. The present study aimed to preliminarily examine the presence of serum specific antibodies against severe acute respiratory syndrome (SARS) -associated coronavirus virus (SARS-CoV) in pediatric SARS patients and explore the possibility of subclinical infection in children/adults through close association with SARS cases.
Methods(1) Clinicians and nurses visited families and collected general and epidemiological information about the subjects using a standard questionnaire and took serum specimens. (2) Specific antibodies against SARS-CoV were assayed with two methods, indirect immunnofluorescence assay (IFA) for detecting IgG antibodies and enzyme linked immunosorbent assay (ELISA) for mixed antibodies. Serum specimens tested included those from 21 clinically confirmed pediatric SARS cases (aged from 8 months to 14 years, 11 male and 10 female) and their 23 parents who had close contact with the children, 36 adult patients in convalescence stage of SARS , 24 children (aged 1.5 to 14 years) and other 34 adults who had close contact with infected adults.
Results(1) The positive rates of specific IgG and mixed antibodies against SARS-CoV were 38% (8/21) and 33%(7/21) in pediatric cases; whereas the rates were 75% (27/36) and 69% (25/36) in adult patients. (2) The proportion of the patients who had close contact to SARS patients was 7/8 among the antibody-positive group vs. 1/13 for the antibody-negative group (P<0.05). (3) The IgG antibody emerged in one of 24 children, whose morther, a nurse, had suffered from SARS (4%). (4) Among 23 parents of children with SARS, one was positive for IgG and the mixed antibodies, whose grandson and husband suffered from SARS; The IgG antibody and the mixed antibodies were also positive in another adult who had close contact with adult SARS cases (3%).
Conclusions(1) SARS-CoV infection was confirmed by serological methods in 38.1% of clinically diagnosed pediatric SARS cases, which leads to the assumption that correct diagnosis of pediatric SARS requires more accurate and efficient ways, for example, screening for antigen or gene of SARS-CoV. (2) The proportion of the patients who had close contact to SARS patients among antibody-positive cases was higher than that in antibody-negative cases. (3) It is possible that subclinical SARS CoV infection exists in children and adults, although the rate of occurrence is low. The data of the present study did not confirm that SARS had subclinical infection among adults who had close contact to pediatric SARS cases.
Key words:
Severe acute respiratory syndrome; Child; Immunoglobulin G; Serologic tests
Contributor Information
CAO Li
The Capital Institute of Pediatrics, Beijing 100020, China
WANG Tian-you
CHEN Hui-zhong
QIAN Yuan
CHEN Bo-wen
FANG Ping
SUN Yan-xiang
ZHU Ru-nan
DENG Jie
ZHAO Lin-qing
MI Jie
ZHANG Ting