I work in the tropical medicine field and have never been able to better the advice from fitfortravel on malaria- linked here:
https://www.fitfortravel.nhs.uk/dest...nd-malaria-map

I ended up taking malaria prophylaxis (doxycycline) when I did Indochina- I was there for 4 weeks and only 1 week was in a malarial zone but because my brain is chronically fried I elected to just take it daily the whole trip
Malarone is light on side effects but expensive