For a trip to Aruba no vaccination is recommended or required. Only a vaccination for yellow fever is mandatory if seven days before your visit to Aruba you've been in a yellow fever country (some countries in Africa and South America).
Dengue fever occurs in Aruba, there is no vaccine available. This virus is transmitted by the Asian tiger mosquito (recognizable by the white pattern on the back). The government has special programs to eradicate the mosquitoes that transmit dengue, but the risk of contagion remains. A mosquito repellent is therefore advisable. Please note the mosquito repellent contains DEET.
If you catch a fever, do not use naproxen, aspirin or ibuprofen. These medicine affect blood clotting in the event that you are infected with Dengue. The use of paracetamol is no problem.
In Aruba there's an above average chance for getting traveler's diarrhea. It is therefore recommended to bring diarrhea inhibitors. Pay attention to eating unwashed vegetables, raw and unpasteurized foods. Wash your hands well after each visit to the toilet and before eating.