It is not a must that you be immunised especially if you are from areas that are not prone to yellow fever( which the authorities will insist on having)
But it is for your own safety and precaution that you get immumnised aganist tetenus because accidents are at times unavoidable,typhoid,yellow fever if you plan to go in areas prone to this disease and cholera
There is no way out with Malaria you have to take larium/whatever the doc prescribes .( Be careful with mephaquine( some type of medicine)it is very strong and should be taken on a full stomach)
This should be taken 4 weeks before travel and then every week 1 tab. and also the first 2 weeks when you are back at home.