Tamiflu is not a vaccine, it is an anti-viral (and only mildly effective at that).
Vaccinations are a numbers game. There are always side effects, but the risk of side effects from the vaccination is so much lower than risk of side effects from the disease that it is worth it. That doesn't mean that someone won't get something from the vaccination, only that on a population level it makes sense.
Why do you think that almost no one gets smallpox vaccinations now? Because the risk from the vaccination is so high compared to the risk of getting the disease (which is now formally eradicated). Basically now only the US military receives smallpox vaccinations.
If the risk from measles is 1 in 20 of getting pneumonia or 1 in 2000 of encephalitis then I think the 1 in millions odds of getting a vaccine complication are worth it.