I assume the connection is based on this quote from the article, "Williams also had been vaccinated for COVID about a month ago and that testing found the two types of antibodies in his system - one type of antibody that results from a natural COVID infection, and a second type of antibody from the vaccine. Threlkeld also said Williams tested negative for COVID-19 while in the hospital."

OR, more specifically this, ". . . and a second type of antibody from the vaccine."