Comment by hirenj

Fun fact: Coronavirus also recognises sialic acids (but they need an extra acetylation on top).

Fun fact 2: Sialic acids are important for protecting your gut / balancing the microbiome.

Fun fact 3: Bats apparently have a much simpler microbiome (less weight, better flying), and can tolerate low levels of coronavirus infection.

I would bet the closest non-flying relative of a bat would get respiratory infections too.