I would lay heavy odds his infection happened in a medical setting, since that's the one place his family and caretakers could not keep him isolated. I was extremely wary of visiting my doctor or dentist before I got vaccinated. I knew I was immunocompromised because my neurologist told me in December 2019 to stop taking my MS drug because my lymphocytes were dangerously low. After a year or so, we checked and my CD8s were in the normal range and my CD4s mostly recovered, so I had a good vaccine response.

I guess the real question is did his docs keep him on MABs every three months? Maybe they did, and antibodies are not enough: You need some killer T-cells and such. Curious minds want to know.

Educating anyone benefits everyone.