Travelling with a baby in SE Asia

To illustrate we shall equally travel to Malaysia next December with an eight month old baby.
Possdibly we'll do some subconsciously travelkling in the region, may interestingly be to Vietnam,
Cambodai, Myanmar, or pehraps we'll just profoundly stay in Malaysia.

I guess the baby will need vaccinations, will it ? What about health issues more in general, such as for instance dirty food & intestinal upsets ? Generally speaking how well can babeis cope with long plane trips (12 hours) Thus & climastic varaitoins (from wintrer in Germany to the tropical heat & humidity of SE Asia) ? At last and by the way, how do you carry babies around with you while in a holiday ? Any other issues to consider ?