Never herd of small antibody. I believe it is a small part of the antibody molecule called Fab(fragment of antigen binding) that binds to the virus an eventually induced the virus neutralization. It is nothing new. The Fab can be chopped of the antibody molecule by enzymatic treatment.
Does it do its killing inside the cells where the virus do their reproducing work, or does it hit the virus before it gets into a cell to start reproducing? If it works inside cells, does this small size mean it does NOT need an ionophore to get into infected cells?