Start with the basics. Before any travel-specific shots, make sure your child is caught up on the normal childhood schedule: MMR, DTaP or Tdap, polio, Hib, varicella, hepatitis B, and rotavirus for babies. Measles still shows up in Indonesia in outbreaks, so MMR timing matters more here than it might back home. Bring your child's vaccination record with you: schools in Bali will often ask for it at enrollment, and a doctor here can't guess what your child has already had.
On top of that, most doctors recommend hepatitis A and typhoid for Indonesia, since both spread through food and water and kids get more exposed once they're eating street food or playing in tap water. Japanese encephalitis is worth discussing if you'll be in Bali longer term or spend time near rice paddies, ponds, or rural areas, since it's mosquito-borne and the risk builds with time spent outdoors. Rabies pre-exposure vaccination comes up a lot for families here too: dogs and monkeys are everywhere, including around temples and beaches, and kids are the ones most likely to pet, tease, or get bitten by one. The pre-exposure series doesn't remove the need for treatment after a bite, but it simplifies that treatment a lot if one happens.
None of this is one-size-fits-all. What your child actually needs depends on their age, what they've already had, how long you're staying, and what your daily life will look like: an apartment in town is different from a rural rice-field homestay. Some of these vaccines need more than one dose spaced weeks apart, so book a visit with your pediatrician or a travel health clinic as early as you can, ideally a couple of months before you move, rather than the week before your flight.
This is general information, not medical advice. For anything specific to your child, please consult a doctor or a travel-health clinic.
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