There are no compulsory vaccinations required for entry to Kenya unless you are arriving from an area infected with Yellow Fever, in which case a Certificate of Inoculation against Yellow Fever is required from travellers older than one year. Visitors coming from other countries in Africa where Yellow Fever may occur, including Ethiopia, Rwanda and Uganda, require a Yellow Fever certificate.
Some countries, including Australia, Bahrain, China, Dubai, India, Indonesia, Malaysia, Mauritius, Oman, Rwanda, Seychelles, Singapore, Tanzania, Thailand and Uganda require arriving visitors from Kenya or elsewhere in East Africa to have a Yellow Fever vaccination certificate. So if you are travelling to one of these countries after a stay in Kenya then you need to have a Yellow Fever certificate.
The other recommended vaccinations are Typhoid, Hepatitis and Polio, and anti-malarial medication is essential. Anti-malarial drugs should be taken prior to arrival and should be continued for 4 weeks after leaving Kenya. It is also advisable to try and avoid mosquito bites by using repellent and by wearing suitable cover-up clothes in the evening.
There are good hospitals in the main towns of Kenya while the rural areas have small health centres where one can get basic first aid. It is absolutely essential that all visitors carry some form of medical insurance to cater for any eventualities. There is an excellent Flying Doctor service in Kenya in the event of a medical emergency, while on safari away from the urban centres. Hotels and lodges supply clean drinking water but whenever in doubt, please drink only bottled mineral water (which is available in hotels and safari camps). Drinking water from the tap is to be avoided.