Both doctors have acknowledged previous failures in attempted coronavirus vaccines and have alluded to the issue of "antibody-dependent enhancement," also called "pathogenic priming." Anthony Fauci, director of the National Institute of Allergy and Infectious Disease (NIAID), has also addressed this potential problem. Let's examine how carefully these problems were examined in the past and how those lessons were or were not applied.

Pathogenic priming

According to a 2009 article published in Expert Review of Vaccines, "The greatest fear among vaccinologists is the creation of a vaccine that is not only ineffective, but which exacerbates disease. Unfortunately, CoV vaccines have a history of enhancing disease, notably with feline CoVs."

Dr. Paul Offit is Director of the Vaccine Education Center at Children's Hospital of Philadelphia. In April, Offit reiterated the concerns about a SARS-CoV-2 vaccine in an interview with Dr. Zubin Damania (better known as ZDogg). In the interview (timestamp 11:53), Offit addressed problems that surfaced with the dengue vaccine, Dengvaxia:

So you have the neutralizing antibodies and you have the binding antibodies. You want to make sure that the quantity of the neutralizing antibodies that you have, and the persistence of those antibodies, is much greater than the binding antibodies. Because the binding antibodies could be dangerous and cause something called antibody-dependent enhancement.