Hi, quite a few if you follow the advice of the CDC, especially if you're going outside Nairobi or to the game parks. All the routine ones you got as a child, plus Hep A, Hep B, Typhoid, Polio, Yellow Fever, Meningitis (if you're there between December and June) and rabies (if you're getting up close and personal with animals in rural areas - that doesn't mean game viewing).
Malaria is not a problem in Nairobi, but it IS in all the game parks. The local strain is resistant to Chloroquine and it's recommended you use Atovaquone/proguanil (daily tablets), doxycycline (brand name Vibramycin), or mefloquine (which has nasty side-effects like paranoia and insomnia!)
Don't rely on the drugs, do everything you can to prevent being bitten in the first place: cover up, sleep under nets and soak yourself in DEET repellant.
We have an extensive article on malaria here:
http://journals.worldnomads.com/safetyhub/post/27111.aspx about 8 years ago
Excellent advice by Phil, who clearly knows a great deal on the topic! That being said, I have been to Kenya a few times and have not had any problems. Yes, I was certain to receive my vaccinations, and I was fairly consistent with my malaria meds (but not perfect, I'm sorry to say). I did have some weird side effcts with Mefloquin- vivid nightmares as well as insomnia, so I have since switched to Doxycycline. Don't forget to being along your immunization card, which shows that you've had your Yellow Fever shots! They may request if from you at customs!!!
-LL about 8 years ago
I agree with the previous poster, Phil covers it pretty well.
In addition to the article he links to, you may also want to consult the frequently updated Centers for Disease Control page on Kenya (http://wwwnc.cdc.gov/travel/destinations/kenya.aspx). almost 8 years ago