OP, #8 is giving you good advice. Check the cdc site. All their childhood vaccinations should also be up to date. Best check with your pediatrician on that because there have been some recent changes.
I recently spoke with a physician at the International SOS clinic in Saigon. Most physicians in Vietnam recommend malaria prophylaxis only for the central highlands and provinces bordering Laos and Cambodia. Vietnam has done a great job controlling malaria, but they can't quite stop the spillover from those two countries.
10

wildbill34
Pro tip