It might not hurt to remind people that the baby just got out of the hospital a very short time ago, so she may already have a stressed immune system. If you can't alter the date, then I think, in this situation, I would go with a strong warning to everybody about being healthy AND washing hands before holding her. It's not a customary thing to do or say, but IMO, the safety and health of the baby trumps being passive and not laying down the law.