Almost 8,000 cases of pertussis, better known as whooping cough, have been reported to California's Public Health Department so far this year. More than 250 patients have been hospitalized, nearly all of them infants and young children, and 58 have required intensive care. Why is this preventable respiratory infection making a comeback.
In the 1990s, when new vaccines were introduced, the news media were obsessed with the notion that vaccines might be doing more harm than good. The measles-mumps-rubella (MMR) vaccine might cause autism, we were told. Thimerosal, an ethyl-mercury containing preservative in some vaccines, might cause developmental delays. Too many vaccines given too soon, the stories went, might overwhelm a child’s immune system.
Then those stories disappeared. One reason was that study after study showed that these concerns were ill-founded. Another was that the famous 1998 report claiming to show a link between vaccinations and autism was retracted by The Lancet, the medical journal that had published it. The study was not only spectacularly wrong, as more than a dozen studies have shown, but also fraudulent. The author, British surgeon Andrew Wakefield, has since been stripped of his medical license.
But the damage was done. Countless parents became afraid of vaccines. As a consequence, many parents now choose to delay, withhold, separate or space out vaccines. Some don’t vaccinate their children at all. A 2006 study in the Journal of the American Medical Association showed that between 1991 and 2004, the percentage of children whose parents had chosen to opt out of vaccines increased by 6% a year, resulting in a more than twofold increase.