Regarding the other vaccinations --
Yellow Fever -- is good for 10 years, and most countries that require immunization records want to see that is was done in that time period.
Typhoid -- not sure how long it lasts, not too many years. There is an oral form (2 capsules) available.
Malaria -- as noted, it has to be taken for each trip. AND DON'T FORGET TO TAKE IT AFTER YOU LEAVE -- malaria can 'hide' in the body for months/years after you leave the area (the record I heard was a WW2 vet getting malaria in the 1980s)
**** As always, please confirm these suggestions with the authorities, as the recommendations change often. I would go to the CDC site.
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Da DOK