Hi Absent Crisis and welcome to Writefix! And thanks for choosing a memorable name!
Your intro is 89 words long, which is dangerously long. Assuming your body paragraphs are in proportion, you will end up with something like this
- Intro 89
- Para 2: 120
- Para 3: 120
- Para 4: 70
...for a total of 400 words or so. That's too long. Aim for about 250-300 words, or maybe 320. It's a challenge. Just ask Katiss what she thinks about word count.
I'd recommend about 55-65 words in the intro, 90-110 in each of the body paragraphs, and another 50 so to finish off. That's about 300 words. If you can do it in less, that's great.
There has been great progress in the medical field on many levels, undoubtedly, one of the most prominent aspect of this development is the invention of the vaccine. It declared the end of many dangerous diseases by reducing and subsequently eliminating their outbreak. Many countries nowadays oblige their citizens to get vaccinated against common infections, especially for children. This essay is going to discuss whether such laws override parents' rights to choose not to immunize their children, or whether they are necessary to insure children's health and well being.
The first three sentences can be safely deleted. Get to the point quickly in your intro and you'll leave more room for the important stuff in the body paragraphs.
From your thesis sentence, it sounds as if you are going to have one paragraph about freedom for parents to decide, and then a paragraph about why countries need rules about vaccination. Is that your plan?