Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea

Abstract

OBJECTIVESThe rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status.METHODSStudy participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results.RESULTSThe asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis.CONCLUSIONSThe asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.

Asymptomatic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection: Extent and implications for infection control: A systematic review

“…A total of 10 papers were retrieved and included in the final analysis and review ( Fig. 1, Table 1) [6,[33][34][35][36][37][38][39][40][41]. We included studies in humans describing the incidence of asymptomatic MERS [6,[33][34][35][36][37][38][39][40] and two additional studies in animals [42,43].…”

“…In a seroepidemiologic survey conducted in South Korea, of 1610 asymptomatic HCWs and non-HCWs contacts only 1 non-HCW (0.06%) tested positive [36]. Asymptomatic persons were identified in the Jeddah outbreak.…”

MERS-CoV as an emerging respiratory illness: A review of prevention methods

“…The average incubation period for MERS-CoV is 5-7 days, but a range of 2 days-14 days have been reported [13,14,[19][20][21][22].The clinical disease spectrum ranges from completely asymptomatic, mild disease and severe disease with multi-organ failure [13,14,[19][20][21][22][23][24][25][26]. In a symptomatic patient, symptoms at presentation may include fever, chills, rigors, myalgia, malaise, cough and shortness of breath.…”

“…Gastrointestinal symptoms of diarrhea, vomiting and abdominal pain may be present as part of the upper respiratory syndrome or as the main presenting complain [13]. Pneumonia is common at presentation [13,14,[19][20][21][22][23][24][25][26]. Severe infection occurs specially among older patients with comorbidities and present with acute respiratory, renal failure and shock [24,25].…”

“…More recent studies suggested up to 50% may be asymptomatic [33]. Differences in the study setting, populations studied, and methods of screening may explain this variability [22,24,27,31,34,35]. Use of serologic testing can underestimate disease burden due to waning antibodies titer over time [15,16,22].…”