"Before traveling to Ghana it is necessary to visit a tropical disease clinic to receive the compulsory Yellow Fever injection for travel in sub-Saharan Africa, a pre-requisite for obtaining a visa to Ghana.
The CDC recommends that, "to have the most benefit, see a health-care provider at least 4–6 weeks before your trip to allow time for your vaccines to take effect and to start taking medicine to prevent malaria, if you need it."
Tropical travel clinics are in the best position to provide the final word on which vaccinations to get, but travelers to Ghana should, at minimum, be vaccinated against polio, tetanus, typhoid, and Hepatitis A and B, all rife in Ghana."
Read more at Suite101: Tropical diseases for travelers in Ghana http://ghana-travel.suite101.com/article.cfm/tropical-diseases-for-travelers-in-ghana#ixzz0nB8FSk5s