If there was a medical need and they were shown to be efficacious, sure. I'm currently receiving allergy shots which involves frequent injections of dust mites

If there was a medical need and they were shown to be efficacious, sure. I'm currently receiving allergy shots which involves frequent injections of dust mites. Injections are followed by a 30 minute observation period as a caution against anaphylaxis. Staff are on hand to intubate. The frequency of life threatening reactions is around 1 in 10^6. If phage were ever used clinically, I suspect the protocol would be similar. I mean, heck, some people have life threatening reactions to common antibiotics (I believe sulfa allergies are particularly common), but that doesn't keep them out of use.