Coevolution and Adaptation of Viral Infections, Susceptible Populations, Evolution of Disease and Variant Creation Related to SARS-CoV-2

Covid-19 has created a major health challenge as a pandemic and demonstrates the threats that human populations face with increased population numbers and density of living situations. Pathogen adaptations to the human immune system are a treat to social complexity and evolution. Present theory argues that human social complexity has advanced in population density due to epidemiologic transition. Globalization and increase human needs for resources with increased density may be reaching limits of the potential for further transitions. The spread of the disease has resulted from mutations making the virus more easily transmitted. Analysis of the viral genome also shows substantial recombination among viral species, quasi-species and variants since an evolutionary event some 5,000 years ago that created several coronavirus groups. Rapid evolution due to recombination and purifying selection of the viral genome, pose a substantial difficulty in producing vaccines and methods of preventing transmission without onerous social distancing and other practices. Typical aspects of the natural history of pathogen infection in mammalian populations that limit the spread, duration and severity of disease (immunity, etc.) appear to be undermined by these features of viral mutation and gene exchange. Breakthrough infections, reinfection after disease and viral escape of vaccines due to evolution of mutations, indicate the possibility of endemic coronavirus in human populations.