Help me understand

I hope this comes across the way I intend it, I’m not trying to push pro or anti vax just trying to understand the logic.

In my country there is currently a debate as measles is making a come back after previously being eradicated for over a decade.

A lot of the comments I’m reading on the news articles discussing vaccine say things about ‘Big Pharma’.

I’m a tad confused because if the large companies were purely after our money wouldn’t they want us to catch these diseases? As in wouldn’t they make more money off ongoing treatment than one immunisation?

Again, not intending to spark debate as to if people should/shouldn’t vaccinate. Just wanting some clarity around the ‘big pharma’ justification so I can understand both sides.

Thanks in advance.