Serologic Testing for Middle East Respiratory Syndrome Coronavirus and SARS-CoV-2 Cross-Reactive Immune Responses, the Netherlands.

Cross-reactive SARS-CoV-2-specific antibodies could compromise the specificity of MERS-CoV serology, potentially leading to misclassification of infection history. SARS-CoV-2 exposure induced MERS-CoV antibodies primarily targeting the conserved S2 domain, with occasional neutralizing capacity. Combining MERS-CoV S1 binding with neutralization, however, limited the influence of SARS-CoV-2-induced cross-reactivity on MERS-CoV serology.