“…This pattern of intrahost evolution results in the formation of mutant spectra that constitute reservoirs of genetic and phenotypic virus variants in the infected host ( 11 , 12 ). Studies with several RNA viruses have shown that viral intramutant spectrum complexity, estimated by the average number of mutations per genome, expressed by a series of diversity indices (Shannon entropy, maximum mutation frequency, Gini Simpson, nucleotide diversity, number of polymorphic sites, and number of haplotypes [ 13 , 14 ]), may have an impact on viral tropism, viral persistence, disease progression, and response to antiviral interventions (several cases have been described or reviewed in references 11 and 15 – 22 ). Evidence of quasispecies dynamics has been reported for SARS-CoV-2 ( 23 – 29 ), as well as for other coronaviruses ( 30 – 34 ).…”