Sensitive and Specific Detection of Low-Level Antibody Responses in Mild Middle East Respiratory Syndrome Coronavirus Infections

• Main Authors: Nisreen M.A. Okba, V. Stalin Raj, Ivy Widjaja, Corine H. Geurts van Kessel, Erwin de Bruin, Felicity D. Chandler, Wan Beom Park, Nam-Joong Kim, Elmoubasher A.B.A. Farag, Mohammed Al-Hajri, Berend-Jan Bosch, Myoung-don Oh, Marion P.G. Koopmans, Chantal B.E.M. Reusken, Bart L. Haagmans
• Format: Article
• Language: English
• Published: Centers for Disease Control and Prevention 2019-10-01
• Series: Emerging Infectious Diseases
• Subjects: Middle East respiratory syndrome coronavirus; diagnostics; enzyme-linked immunosorbent assay; spike; MERS; S1
• Online Access: https://wwwnc.cdc.gov/eid/article/25/10/19-0051_article
• ISSN: 1080-6040; 1080-6059

Middle East respiratory syndrome coronavirus (MERS-CoV) infections in humans can cause asymptomatic to fatal lower respiratory lung disease. Despite posing a probable risk for virus transmission, asymptomatic to mild infections can go unnoticed; a lack of seroconversion among some PCR-confirmed cases has been reported. We found that a MERS-CoV spike S1 protein–based ELISA, routinely used in surveillance studies, showed low sensitivity in detecting infections among PCR-confirmed patients with mild clinical symptoms and cross-reactivity of human coronavirus OC43–positive serum samples. Using in-house S1 ELISA and protein microarray, we demonstrate that most PCR-confirmed MERS-CoV case-patients with mild infections seroconverted; nonetheless, some of these samples did not have detectable levels of virus-neutralizing antibodies. The use of a sensitive and specific serologic S1-based assay can be instrumental in the accurate estimation of MERS-CoV prevalence.