Aruba did require vaccinations when COVID was at its height, but it no longer requires any proof of vaccinations to enter the country, though it's wise to be up to date on routine vaccines.
The one exception is: travelers arriving in Aruba from areas with a risk of yellow fever are required to have a valid vaccination against yellow fever. We recommend visiting the CDC website or consulting your doctor to find out if this applies to you based on where you're traveling from. The list includes countries in Central and South America (like Brazil, Colombia, Peru, Venezuela, Bolivia, and several others) and many African nations. If you're coming from one of these countries or transiting through them for more than 12 hours, you'll need proof.
The yellow fever vaccine must be administered at least 10 days before your arrival to be valid, and you'll need to show your International Certificate of Vaccination or Prophylaxis (the "yellow book") to immigration officials. Exemptions exist for children under 9 months, adults over 60, pregnant or breastfeeding women, and those with certain medical contraindications—though you'll need a medical waiver for health-related exemptions. If you're traveling from a yellow fever risk country but stayed in a non-risk country for at least 6 days without developing symptoms, you're also exempt.