Zanzibar is not an official Malaria area anymore. It is up to you to take Malaria prophylaxis or not. Do bring Mosquito repellent and drink lots of Tonic water (Mosquitos hate the smell of chinine in the tonic water which your skin somehow gives off). If you drink alcohol, enjoy a gin tonic at sunset (gin also contains chinine = double dose of chinine) – the gin tonic is only to keep the Mosquitos away of course 🙂
In the hotel rooms, you have mosquito nets and staff usually spray the rooms at night when they get your bed ready.
YELLOW FEVER VACCINATION
Officially, a yellow fever vaccination is only mandatory if you arrive from yellow fever endemic countries. It is not required if you arrive from any other countries. Please see official confirmation letter of the Zanzibar Ministry of Health below, dated 10 August 2017.
Having said that: When I returned from a trip to South Africa with Kenya Airways, via Nairobi (transit only), everyone was asked for the yellow fever certificate! In case you are coming from Kenya, transit or not, rather have the yellow fever certificate. It is a good idea anyway to get that shot since you are covered for life then. There is still no cure in case you get yellow fever!
MEDICAL CARE / HOSPITALS
In case you should require medical attention, we have so-called Clinics in the bigger villages that are run by qualified nurses, they can also administer antibiotics if needed.
Alternatively, I recommend Tasakhtaa Global Hospital in Vuga, Stone Town. It has modern equipment (which is not the norm on the island), excellent doctors (mainly from Ukraine and India) and an emergency section: http://www.tasakhtaahospital.co.tz
Reception for making an appointment: +255 (0) 24 223 2341
Emergencies: +255 (0) 24 223 2222, if you need an ambulance +255 (0) 779 770 577
For a General Practitioner in Stone Town I recommend ZanAid Clinic in Mbweni, about 2km from the airport. Please rather make an appointment beforehand: +255 777 777 112 or firstname.lastname@example.org or book an appointment online http://www.zanaid.org.
They are off Chukwani Road, follow the sign, after the second sign turn left and turn right at the very next road (the sign there apparently keeps on dissappearing). Look out for a big white house with a gate, and the sign ZanAid Clinic.
Should you get sick in a coastal area, best contact the manager or reception of your place of accommodation, they should have the numbers of the nearest medical practitioner
Pharmacies: Shamshu (best selection) and Izmir Pharmacies, both in Darajani/Stone Town, behind the fish/meat market building, and at Global Hospital
In the rural areas, there are small Dawa (Kishwahili for medicine) shops, but they are badly stocked.
I suggest that you bring an emergency travel kit (especially antibacterial ointment) which you could donate to the local clinic when you leave, it will be much appreciated.