They prove beyond any legitimate doubt that vaccines are so effective that the very small segment of the population that cannot tolerate them are effectively shielded by the herd immunity.
Of course, you are aware that due to medical inability for 6% of people to be vaccinated, and a non-zero vaccine failure rate, and the fact that we do not perform post-vaccination immunoassay to verify that the vaccination has been effective (and then revaccinate the shit out of the person until an immunoassay shows it to be effective), therefore herd immunity for measles and pertussis is mathematically impossible.
Right?
You *should* get vaccinated for these diseases, and you *should* get your kids vaccinated for these diseases. If the vaccine is effective, which for measles, it is 61% of the time according to a recent WHO study in Buenos Ares, Argentina, then you've saved your ass, or you've saved your kids ass.
But you are totally a moron if you believe that you are doing this out of altruism, rather than out of a selfish desire to save your own ass, because you will not, in fact, prevent either outbreaks or spread of these two diseases.
Particularly if we let people from hot zones with known active outbreaks fly into the U.S. with no border procedures to prove they don't have the diseases, and then let them go to Disneyland and infect the 39% of the 94% who are vaccinated (but for which the vaccine was ineffective), or the additional 6% who are immunocompromised to the point they can't tolerate being vaccinated.
P.S.: Now if you want to pick a different example, like Polio, chickenpox, or smallpox: yes, it's possible to achieve herd immunity. But most idiots who are bad at math tend to use measles or pertussis as their examples, because the outbreaks are always in the news (hint: because they are impossible to prevent via any method other than quarantine, and that's politically correct, even if we are talking about Ebola, for which there is no vaccine).