Coronaviruses and Acute Respiratory Syndromes (MERS and SARS) By Brenda L Tesini, MD, University of Rochester School of Medicine and Dentistry Reviewed / Revised Apr 2022 | Modified Sep 2022 View Patient Education Middle East Respiratory Syndrome (MERS) Symptoms and Signs Diagnosis Treatment More Information Severe Acute Respiratory Syndrome (SARS) Topic Resources Emerging Coronaviruses Coronaviruses are enveloped RNA viruses that cause respiratory illnesses of varying severity from the common cold to fatal pneumonia.