This needs more info.

“Once infected patient” does this mean the patient was really infected? If indeed it was already a diagnosis of Rabies then there is no turning back. There are documented sucess in treating Rabies but the cure rate is low, that is why it is recommended to get a pre- and/or post-exposure prophylaxis.

Latent infection - yes this happens when the virus travels somwhere in the nervous system and be dormant, then wakes up one day due to a trigger factor. This is caused by insufficient doses of the vaccine given, or no vaccine was given at all. So better get all the shots recommended for post-exposure prophylaxis. Especially important to note is one has to get both the passive and active vaccines to prevent latent infection.

Booster doses - from where I am (PH), booster doses after the initial doses are not really required, as evidenced by local and international journals. The full post-exposure prophylaxis is sufficient. However, if you are highly exposed to animals (eg. You live in a farm, have many mammalian pets, you are a hunter or is involved in any activity that may cause you to get bitten like a vet, etc), pre-exposure prophylaxis is recommended.