Despite what was learned within the last decades about coronaviruses, and even more so within the last year, there are a number of remaining knowledge gaps regarding the latest SARS‐CoV−2 infection
First, it is not known what the original source or the intermediate hosts of SARS‐CoV‐2 are (Table 1). It is also not completely understood which transmission ways are relevant, neither for interspecies transfer for animals, nor cross‐species‐wise in a zoonotic way from animals to humans (which are relevant?), or reverse‐zoonotic way (do infected humans pose a differing risk to different animal species in close proximity?)
In all species, the efficacy of an established immune response against SARS‐CoV‐2 (eg, neutralizing antibodies) as well as its duration are not known, due to the short duration of the pandemic (1.5 years).
Mutations of SARS‐CoV‐2 take place roughly every two weeks. More than 20 genetically stable mutations might have taken place already since the outbreak, however, for many the impact on the infectibility, transferability, disease severity, and treatment are not known, both for humans and animals.