By comparing the measles and polio vaccines to the flu vaccine to obesity, you are trying to compare apples, oranges and a chocolate bar. It doesn't work.
1. The incidence of polio and measles is low BECAUSE OF VACCINATION. High levels of vaccinations over time has reduced the incidence to very low levels, but not so low that the vaccinations can be stopped, as is the case with smallpox. If people keep up the vaccinations on these diseases, then in a generations time, we may be able to stop because the disease has been eradicated. But, while there are people opposing vaccination based on one flawed and since retracted study, then the eradication will not happen. Unvaccinated people will
probably be fine due to herd immunity, as long as a non zero number of people catch the disease, then on it goes.
2. The flu vaccine is a different beast - each year a vaccine is produced based on the current seasons strain. Since the flu virus mutates so quickly, last years vaccine is useless this year, and whatever vaccine is produced next year is useless today. The flu shot is not mandatory because it would be wildly impractical to expect everyone to get the shot every year, but it is recommended for high risk demographics.
3. Obesity is a completely different argument - it is a chronic condition that comes on over time, and can be reversed at any time, unlike the diseases above. And where do you draw the line?
I am not going to look up the numbers, but I know they would be there if you go digging at
http://abs.gov.au/
Anyway, for measles, I would say not many, but since it is 100% preventable by simple means, then the government has taken steps to ensure that it is 100% prevented.
For the flu, a few more, but as I mentioned above, vaccination is a year to year prospect, and most of the flu deaths are in people who have other conditions (age, immunocompromised etc).
For obesity, too many, but that is completely irrelevant to this argument. Besides, kids who become blimps are generally known to a doctor of some sort, who would be trying to manage the case.
That is enough time wasted typing this - I need to get some work done today so I can leave work early tomorrow to get my daughter's first immunisations done.