Whether to use prophylactics is a risk-benefit analysis question. You need to evaluate the malaria risk in the parts of Belize you are going to, the type of travel you will be doing, and your current health and susceptibility to adverse reaction from prophylactics.
Unfortunately, public advisory resources do not provide that analysis and therefore, their info is suspect.
My opinion, based on the info I have, is that the risk of catching malaria if your vacation is to be limited to a beach vacation on Ambergris Caye is very close to zero (nothing is ever zero). That is because the number of people who have malaria on AC is relatively small (and usually limited to people who have recently arrived from other parts of Belize and especially from other Latin American countries). Because there are so few residents with malaria for mosquitos to bite and thereby become vectors, there are very few known instances of visitors becoming infected. Also, most resorts and hotels spray regularly. In the dry season there is not much standing water; the biggest buggie nuisance is no see ums and they are not malaria carriers.
I have never used prophylactics and do not plan to in the future for visiting AC.
There is quite a bit of malaria in the Toledo and Cayo Districts, primarily in poorer areas. Here again, there are few if any known instances of tourists catching malaria in tourist resorts in those areas.
Most of the foreigners who have gotten it have been people who were taking extended trips into the bush and camping out If I was doing that, I would take a chloroquine prophylactic. I do not do so for visits to Cayo resorts.
Also, I am unaware of any choloroquine resistant malaria in Belize, so the more deleterious anti malaria prophylactic should not be prescribed under any circumstances (this is a dangerous drug with many side effects; choloroquine can cause side effects but less frequently and less deadly.)
If you are going into an area that has a lot of "bush" and standing water, you can protect yourself by wearing long pants and shirts and dousing yourself with "Off" or some other substance that contains DEET. Do that if you are bike riding or walking in the jungly areas outside of town.
Susan Guberman-Garcia, Attorney at Law. Phone: 510-792-2639
Fax/Voicemail:: 510-405-2016 Email: firstname.lastname@example.org