Since the duration of fever is three days.Its not a fever due to Vaccination.a fever after vaccination will not persist more than 24 hrs. .according to your history other than fever no other focus of infections like cough,cold,loos stools,no throat congestions,burnin micturition,no lymphadenopathy,etc..
So i think it is viral fever.
Next Steps
paracetamol 4 times a day for two days
if fever persist more than two days.routine blood and urine test is my opinion.