Obviously from an infected person. But we're talking about the initial rollout of the vaccine. You're not going to have enough vaccinations available to immediately wipe out the virus. So do you use the initial resources to protect the most vulnerable and slowly vaccinate the rest of the population that has a better chance of fighting off the virus with their own immune system, or do you vaccinate the vulnerable folks last? I'm not saying one way or another is the right approach - I'm just offering a different perspective.