I had previously erroneously stated that the Moderna and Pfizer vaccines contained mRNA encoding only the spike receptor-binding domain; this was an error on my part. With so many vaccine candidates, including those that did use only the receptor-binding domain, I must have gotten confused. Both of these vaccines encode a pre-fusion stabilized (with a double proline substitution) full-length spike protein. I have gone through and corrected all erroneous references on the blog and regret this error. I will strive to be more diligent so as to not make such careless mistakes in the future.