science

Active macrophages can damage healthy cells. It's a very serious condition when they do, and it can lead to runaway cellular death. It doesn't mean that this treatment will cause MAS, but it's a risk that should be investigated with human trials.

It also has a metabolic cost, in that the active cells consume energy and oxygen, but I don't know if it would be a noticeable effect for the average person.

My guess is that this would be something you use when you are at increased risk for cold and flu. Like nurses and doctors, teachers and childcare workers, and nursing home staff during the fall and winter.