I would be more worried about the child's immune system, it may still be weak and going into a country with lower sanitation standards and tropical environment, I do not think medically it would be a good Idea. Wait until your child's immune system is stronger and immunized for tropical diseases and hepatitis. I would see a doctor that specializes in tropical medicine before you decide to take your vacation. But Manila per say is just like any other city, there are good parts and parts you want to avoid. If you stay in the secured tourist areas there and use common street sense should not be a problem, the hill country is another story pockets of communist and Jihadist fighting there.