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Review
. 2019 Jan 31;41(1):69-81.
doi: 10.1093/epirev/mxz009.

A Review of Asymptomatic and Subclinical Middle East Respiratory Syndrome Coronavirus Infections

Rebecca Grant, Mamunur Rahman Malik, Amgad Elkholy, Maria D Van Kerkhove
Review

A Review of Asymptomatic and Subclinical Middle East Respiratory Syndrome Coronavirus Infections

Rebecca Grant et al. Epidemiol Rev. .

Abstract

The epidemiology of Middle East respiratory syndrome coronavirus (MERS-CoV) since 2012 has been largely characterized by recurrent zoonotic spillover from dromedary camels followed by limited human-to-human transmission, predominantly in health-care settings. The full extent of infection of MERS-CoV is not clear, nor is the extent and/or role of asymptomatic infections in transmission. We conducted a review of molecular and serological investigations through PubMed and EMBASE from September 2012 to November 15, 2018, to measure subclinical or asymptomatic MERS-CoV infection within and outside of health-care settings. We performed retrospective analysis of laboratory-confirmed MERS-CoV infections reported to the World Health Organization to November 27, 2018, to summarize what is known about asymptomatic infections identified through national surveillance systems. We identified 23 studies reporting evidence of MERS-CoV infection outside of health-care settings, mainly of camel workers, with seroprevalence ranges of 0%-67% depending on the study location. We identified 20 studies in health-care settings of health-care worker (HCW) and family contacts, of which 11 documented molecular evidence of MERS-CoV infection among asymptomatic contacts. Since 2012, 298 laboratory-confirmed cases were reported as asymptomatic to the World Health Organization, 164 of whom were HCWs. The potential to transmit MERS-CoV to others has been demonstrated in viral-shedding studies of asymptomatic MERS infections. Our results highlight the possibility for onward transmission of MERS-CoV from asymptomatic individuals. Screening of HCW contacts of patients with confirmed MERS-CoV is currently recommended, but systematic screening of non-HCW contacts outside of health-care facilities should be encouraged.

Keywords: MERS-CoV; health-care workers; infection control; seroprevalence; subclinical infections.

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Figures

Figure 1
Figure 1. Flow diagram of selection of articles for the review of symptomatic and subclinical Middle East respiratory syndrome coronavirus (MERS-CoV) infections. Additional records identified through consultation with the World Health Organization MERS technical network and in the bibliography of a related review (19).
Figure 2
Figure 2. Epidemic curve of laboratory-confirmed Middle East respiratory syndrome coronavirus infections among A) health-care workers and B) non–health-care workers and outcome reported to the World Health Organization from 2012 to November 27, 2018.
See this image and copyright information in PMC

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