Ecological and Molecular Evidence for Pre-2020 Circulation of hCoV-19 Ancestors and the Complexity of the Human Respiratory Virome

The global detection of hCoV-19, identified as the causative agent of COVID-19, has sparked intense investigation into its origins and potential pre-2020 circulation. This paper proposes that hCoV-19 or its precursors likely circulated globally at sub-detection levels before the declared pandemic, evading standard surveillance due to technical limitations in detecting divergent or low-abundance viral lineages. Drawing parallels with the discovery of \textit{Redondoviridae}, a prevalent yet previously undetected viral family identified through advanced metagenomic sequencing, we highlight the challenges of detecting low-abundance viruses within the complex human respiratory virome. Retrospective molecular and serological evidence, including wastewater analysis and NCBI Sequence Read Archive (SRA) data, supports the presence of hCoV-19-like sequences predating 2020, suggesting cryptic spread and asymptomatic carriage as key drivers of its persistence and evolution. The author argues that hCoV-19 exists within a dynamic equilibrium of \textit{Betacoronavirus} diversity, with its 2020 emergence reflecting ecological complex dynamics rather than a singular novel zoonotic event. This ecological perspective frames COVID-19 as a severe manifestation within the continuum of respiratory illnesses, influenced by multifactorial host, environmental, and societal factors. Focusing on advanced sequencing technologies and nuanced public health approaches that acknowledge the complexity of the human virome is essential for enhancing the understanding of viral dynamics and effectively mitigating future outbreaks.