The CDC recommends that travelers make sure they are updated with all basic immunizations. That means against measles, mumps, rubella (or the multifunction MMR vaccine), diphteria, pertussis, tetanus (or the multifunction DPT vaccine), polio, and other standard immunizations. If you are not immunized against tuberculosis, it may make sense to get vaccinated.
Anyone over 9 months of age should get yellow fever immunizations for travel to sub-Saharan Africa, according to the CDC. The vaccine must be given 10 days before departure. The CDC also lists all authorized yellow fever immunization clinics in the U.S., see Reference 2.
Hepatitis A spreads through food and water, and may occur even in countries with standard tourist facilities. All of Africa is a risk area, including South Africa and the Saharan region. The CDC recommends immunizations for all travelers.
Hepatitis B spreads through blood and other bodily fluids, and anyone who is likely to come into contact with those should get vaccinated, according to the CDC. This also applies to people who may be taken to hospital because of an accident.
Typhoid spreads through food and water, and is especially common in rural areas, outside major cities. Travelers who visit people in their homes in rural areas are especially at risk. The CDC recommends immunizations for all travelers who have not been vaccinated before.
Anyone spending time outdoors should get immunized against rabies, according to the CDC. They especially caution to get children immunized, as they may play with animals who can be infected.