Epidemiology and Infection

Systematic Review

Seroprevalence of IgG antibodies to SARS-coronavirus in asymptomatic or subclinical population groups

G. M. LEUNG a1a2c1, W. W. LIM a3, L.-M. HO a1, T.-H. LAM a1, A. C. GHANI a4, C. A. DONNELLY a4, C. FRASER a4, S. RILEY a4, N. M. FERGUSON a4, R. M. ANDERSON a4 and A. J. HEDLEY a1
a1 Department of Community Medicine, University of Hong Kong, Pokfulam, Hong Kong, China
a2 Takemi Program, Harvard School of Public Health, Boston, MA, USA
a3 Government Virus Unit, Public Health Laboratory Centre, Shek Kip Mei, Kowloon, Hong Kong, China
a4 Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College, University of London, St Mary's Campus, Norfolk Place, London, UK

Article author query
leung gm   [PubMed][Google Scholar] 
lim ww   [PubMed][Google Scholar] 
ho lm   [PubMed][Google Scholar] 
lam th   [PubMed][Google Scholar] 
ghani ac   [PubMed][Google Scholar] 
donnelly ca   [PubMed][Google Scholar] 
fraser c   [PubMed][Google Scholar] 
riley s   [PubMed][Google Scholar] 
ferguson nm   [PubMed][Google Scholar] 
anderson rm   [PubMed][Google Scholar] 
hedley aj   [PubMed][Google Scholar] 


We systematically reviewed the current understanding of human population immunity against SARS-CoV in different groups, settings and geography. Our meta-analysis, which included all identified studies except those on wild animal handlers, yielded an overall seroprevalence of 0·10% [95% confidence interval (CI) 0·02–0·18]. Health-care workers and others who had close contact with SARS patients had a slightly higher degree of seroconversion (0·23%, 95% CI 0·02–0·45) compared to healthy blood donors, others from the general community or non-SARS patients recruited from the health-care setting (0·16%, 95% CI 0–0·37). When analysed by the two broad classes of testing procedures, it is clear that serial confirmatory test protocols resulted in a much lower estimate (0·050%, 95% CI 0–0·15) than single test protocols (0·20%, 95% CI 0·06–0·34). Potential epidemiological and laboratory pitfalls are also discussed as they may give rise to false or inconsistent results in measuring the seroprevalence of IgG antibodies to SARS-CoV.

(Published Online July 22 2005)
(Accepted April 21 2005)
(July 22 2005)

c1 Department of Community Medicine, Faculty of Medicine, University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China. (Email: gmleung@hkucc.hk)