Chinese grammar (about a prepositional phrase)?

I know nothing about Chinese grammars, let’s go this way.
“为” it means for the purpose of.
The whole sentence after“为”-- 防止MERS疫情重创韩国经济, is a purpose for the “为”. You can also say or write “为了”, the meanings are totally the same.
Before your second question, my opinion is -- if Chinese have grammar rules, then very possibly, we have very different grammar rules compared with English.
Now, back to your second question, you think 防止 is a verb, I think it’s right; but just add “的/Pinyin - de”, the phrase -- 防止的, it becomes an adjective. About this, I think you have already known it.
We normally don’t use 防止 as a noun, but be careful, similar words like 妨碍/obstacle/ fáng ài、防范/prevent/ fáng fàn、防卫/guard/ fáng wèi, 防守/defend /fáng shǒu, etc., have the functions of verb and noun. And more, even we use 防止 as a noun, ex, we have already done some 防止, it just like collective adjective in English, there’s no problem to understand, and it just sounds a little informal.
Oh, I’m an English learner, I have a lot of questions on English grammars which I know that you never have the problems as we have.
Point is to understand each word’s basic meaning and extended meaning – The way I do in English learning.
Good lucks.

防止 here is an infinitive and 'to' can be followed by an infinitive