Prevalence of subclinical infection by the SARS coronavirus among general practitioners in Hong Kong

Abstract

Eight general practitioners had severe acute respiratory distress syndrome (SARS) in Hong Kong during the epidemic, and others may have been infected by the SARS coronavirus without developing the full syndrome. We conducted a serological and questionnaire survey to determine the prevalence of subclinical infection by SARS coronavirus among general practitioners in Hong Kong. Participants had to be doctors actively practising in family medicine and who did not have SARS. Approximately 3200 general practitioners were invited to participate and the results of 574 were eligible for analysis. 29 samples were tested positive by enzyme-linked immunosorbent assay, but all these samples had titre < 25 by immunoflorescence assay. The prevalence for seropositivity was thus 0% (95% CI, 0.0%-0.6%). This finding documents the lack of subclinical infection by SARS coronavirus in an at-risk group in the community.

Severe Acute Respiratory Syndrome Coronavirus as an Agent of Emerging and Reemerging Infection

“…In 17 studies that reported on seroepidemiology, the seroprevalence varied from 0 to 1.81% for the general population, 0 to 2.92% for asymptomatic health care workers, 0 to 0.19% for asymptomatic household contacts, and 12.99 to 40% for asymptomatic animal handlers (28,37,45,69,117,141,198,201,203,207,209,228,352,369,387,406,429). The last finding is quite expected, since frequent zoonotic challenges by lowlevel-pathogenic strains of SARS-CoV before 2003 in animal handlers of southern China would probably have caused such a high seroprevalence in this at-risk group.…”

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

“…A total of 16 studies, from five SARS-affected regions (Beijing, Guangzhou, Hong Kong, Singapore and Toronto), were identified [4,5,[8][9][10][11][12][13][14][15][16][17][18][19][20][21] (Table) There is wide variation in the reported seroprevalence of antibodies against SARS-CoV which is strongly associated with the characteristics of the subjects tested (indicating a priori risk of infection) and the laboratory methods employed to determine seroconversion.…”

Seroprevalence of SARS Coronavirus Among Residents Near a Hospital with a Nosocomial Outbreak

“…24 In particular, because "common cold"-associated coronavirus infections are highly prevalent, whole virus-based assays, which have low specificity, cannot be used for the diagnosis of SARS-CoV. 19 In our case, although 124 subjects were seropositive based on ELISA, we confirmed SARS-CoV infection in only two patients by the more precise and specific IFA. Similar results have been reported in a seroprevalence study of SARS infection of general practitioners in Hong Kong, in which 5.1% tested positive by ELISA but none tested positive by IFA.…”

“…Another SARS seroprevalence study of 574 general practitioners in Hong Kong found 0% infection rate of SARS-CoV in the at-risk group. 19 Even in hospital settings, however, the seroprevalence of SARS in health care workers is still not high. For example, a seroprevalence study of 193 emergency department workers exposed to SARS in a Taiwanese medical center found that the incidence of SARS-CoV infection was only 4.7% (9/193).…”