Multiple systematic reviews, meta-analyses, and large cohort studies consistently demonstrate that the incubation period (contraction-to-contagion/symptom duration) for COVID-19 spans several days, typically averaging between 3 and 6.5 days depending on the variant.
The retrieved papers consistently report mean or pooled incubation periods for COVID-19 lasting multiple days (ranging roughly from 3 to 6.5 days across different strains and studies). This directly supports the claim that the duration spans several days.