“…For vaccine development, such probes can be used to define and monitor the elicited responses, and for antibody characterization, such probes can serve as critical molecular tags, facilitating the identification of the highly effective antibodies which could be used for passive therapy (Cao et al, 2020;reviewed in Casadevall et al, 2004;Graham and Ambrosino, 2015;Walker and Burton, 2018). In diagnostics, they can be employed to assess sera reactivity and to provide sensitive markers of infection (Perera et al, 2020;Yan et al, 2020b;Zhao et al, 2020). In pathogenesis, they can assist in delineating susceptible cells that virus might infect or in tracking viral variants, including those that might have selective advantages (Korber et al, 2020).…”