I see two problems with this approach, both political / social:
- No one will want to be the one "deploying" the attenuated strain in a human and then be responsible for some unforeseen death (even if it's just 1 in a billion). Utilitarianism is not widespread nor socially accepted. Even less so in politicians, who are quite risk averse.
- There is no lobby supporting it. There's no $$ to be made and the "vaccine" is basically free.
- No one will want to be the one "deploying" the attenuated strain in a human and then be responsible for some unforeseen death (even if it's just 1 in a billion). Utilitarianism is not widespread nor socially accepted. Even less so in politicians, who are quite risk averse.
- There is no lobby supporting it. There's no $$ to be made and the "vaccine" is basically free.