Unless you are coming from a fellow fever country or where yellow fever is classified as an endemic no vaccination certificated are required to visit Mauritius.
It isn’t a bad idea to pack a pair of shoes that can be worn in the ocean to protect against sharp coral, urchins or stonefish. Stonefish stings are very rare but in some cases they can be fatal. Many hotels do stock anti-venom serum in case of a sting and it is highly advisable to seek medical attention urgently should you be stung.
Bottled water is widely available and it is advisable to drink only bottled water. Medical facilities are free in public hospitals; however private clinics are costly and it is always advisable to take travel insurance when traveling.