INTRODUCTION: Important points in cough management are that it is necessary to be familiar with the characteristic medical history for each disease, such as infection and cough variant asthma. To clarify whether cough due to SARS-CoV-2 has any characteristics or not, we investigated the clinical manifestations of COVID-19 Omicron variant focused especially on infectious cough. METHODS: We enrolled adult patients consecutively diagnosed with mild COVID-19 who were medical healthcare workers in our five hospitals. A total of 2,449 patients were analyzed: 300 patients with BA.1 subvariant, 202 patients with BA.2 subvariant, 1,030 patients with BA.5 subvariant, 413 patients with XBB lineage, 103 patients with BA.2.86, and 401 patients with JN.1 subvariant. RESULTS: Among the clinical symptoms, cough was most frequent symptom in all Omicron subvariants groups and all age groups. The most frequent pattern of symptoms was cough appearing after pharyngeal symptoms in 38% of patients, with cough appearing after fever observed in 25.1% of patients. The pattern in which cough and pharyngeal symptoms were the initial symptoms was observed in 19.6% of cases, and where cough and fever were the initial symptoms was observed in 14.9% of cases. CONCLUSIONS: Cough was the most frequent symptom in patients with COVID-19 Omicron variant and cough was the initial symptom in 1/3 of cases, and 2/3 of cases were preceded by symptoms other than cough. There were few cases of cough only or paroxysmal cough. However, it is considered difficult to differentiate between sources of infectious cough based on symptoms alone.