Vaccine effectiveness

From the Star & Sickle:

A mumps vaccine was introduced in 1967. Iowa law requires schoolchildren to be vaccinated against measles and rubella, and the mumps vaccine is included in the same shot. The state’s last major outbreak was in 1987, when 476 people were infected.

Of the 245 patients this year, at least 66 percent had had the recommended two-shot vaccination, while 14 percent had received one dose, the Public Health Department said.

“The vaccine is working,” Quinlisk said. “The vaccine certainly was made to cover this particular strain, because it’s a fairly common strain of mumps.” Quinlisk said the vaccine overall is considered about 95 percent effective.

So, the question is this: if the vaccine, not improved hygiene or some other factor, is primarily responsible for preventing transmission of the disease it is supposed to prevent, how is it possible that 80 percent of the infected in this latest outbreak are at least partially vaccinated against it?

And isn’t it at least somewhat doubt-inspiring that the health authorities continue to insist that the vaccine is working in the face of direct evidence that, at least in some cases, it is not?