Dogs should sleep where they are comfortable sleeping.
If your dog wants to sleep in their own dog bed or on a blanket then they can do so.
Or if the dog wants to sleep in your bed with you and you will allow the dog to sleep in your bed with you then that is fine as well.
There's nothing wrong with a dog sleeping in the bed with humans and you will not get any worms or other disease from the dog from allowing the dog to sleep in the same bed as you.
I have a dog that sleeps sometimes sleeps with me next to me in my bed and has done so for 10 years now and I have never gotten any worms or any illness from the dog sleeping with me.
However sometimes the dog sleeps in a dog bed when he prefers too.
I just let my dog sleep wherever he wants to sleep.