Hello and welcome! We'd love to see pictures of your lorikeet.
Unlike other animals like dogs and cats, birds don't get vaccinated or receive preventative worming medication. You should be getting your new one to a certified avian vet yearly though for a wellness check/physical, if you want you can have gram stains done to check for diseases and ensure your bird is in tip-top shape!
As for bathing, what do you mean by 'full bath' ? You can give him a 'full bath' with a spray bottle, by providing him a shallow dish of water so he can bathe himself, or you can take him in the shower (many buy parrot shower perches for this) and let water cascade over him. Any of these ways will work, but never use shampoo or conditioner on him, a purely water bath daily or weekly will be sufficient to keep his feathers looking healthy and clean.