Scholastic publishers have these 'Hello Reader!' series that I am personally quite fond of. They are age appropriate and offer varied options according to the reading ability of the child.
I quite like the book on Germs that has great rhymes and fun illustrations to drive some key messages home.
We're on the ground,
We're in the air.
and we live everywhere!
Knock-knock, body. Let us in!We'll make you sick once we begin!
Every germ thinks it's just grand
to hop in a mouth on a dirty hand.
Written by Bobby Katz and illustrated by Steve Bjorkman , the book is written from the perspective of germs and when they are happy attacking you and your body and when they get shut out. Informative about what helps germs multiply and what keeps them away and also some facts about your body. They have some fun names like "hurry ups" who don't flush or wash after potty, "nose pickers", "sneezers" and "coughers" that make kids laugh. This makes the health and hygiene lesson fun instead of preachy. Nicely done! My kid's school library also has it and the teacher has read it out to them. So in my opinion, very useful for any educator or parent.