BACKGROUND: The coronavirus disease 2019 (COVID‐19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) remains a major global health concern in 2022. The association between the rapid spread of the variants, which eliminated the original strain, and clinical manifestations with the variants remains undetermined. METHODS: This was a population‐based longitudinal cohort study. Whole citizens in a city with approximately one million population who had contacted COVID‐19 patients and were tested by nasopharyngeal SARS‐CoV‐2 reverse transcription‐polymerase chain reaction (RT‐PCR) swab test between July 2020 and March 2021 were enrolled. Detailed contact episode and the presence of cough symptoms 4–5 days after contact with patients having COVID‐19 were evaluated. RESULTS: Among the 359 RT‐PCR test‐positive patients, 88 (24.5%) developed cough symptoms by 4–5 days from the infection. The same rate in RT‐PCR test‐negative cases was 8.6%. The prevalence of cough did not significantly differ by age, sex, and places or closeness of the contact episode. The rate of cough symptoms in RT‐PCR test‐positive patients increased in February–March 2021 with E484K variant predominance compared to that in July–December 2020 with the original strain (32.9% vs 19.4%, p = 0.0221), whereas the cough prevalence among RT‐PCR test‐negative population did not increase. Cough symptoms in COVID‐19 patients was associated with strong fatigability, but was independent from fever or dysosmia. CONCLUSIONS: Cough symptoms 4–5 days after infection with SARS‐CoV‐2 was suggested to have increased with E484K variant, compared to the original strain.
Variation in the prevalence of cough symptoms 4–5 days after infection with SARS‐CoV‐2 between seasons with different prevalent strains