In a highly unusual outbreak of measles here last month, 12 children fell ill; nine of them had not been inoculated against the virus because their parents objected, and the other three were too young to receive vaccines.
The parents who objected to their children being inoculated are among a small but growing number of vaccine skeptics in California and other states who take advantage of exemptions to laws requiring vaccinations for school-age children.
The exemptions have been growing since the early 1990s at a rate that many epidemiologists, public health officials and physicians find disturbing.
Children who are not vaccinated are unnecessarily susceptible to serious illnesses, they say, but also present a danger to children who have had their shots — the measles vaccine, for instance, is only 95 percent effective — and to those children too young to receive certain vaccines.
Measles, almost wholly eradicated in the United States through vaccines, can cause pneumonia and brain swelling, which in rare cases can lead to death. The measles outbreak here alarmed public health officials, sickened babies and sent one child to the hospital.
Every state allows medical exemptions, and most permit exemptions based on religious practices. But an increasing number of the vaccine skeptics belong to a different group — those who object to the inoculations because of their personal beliefs, often related to an unproven notion that vaccines are linked to autism and other disorders.
Twenty states, including California, Ohio and Texas, allow some kind of personal exemption, according to a tally by the Johns Hopkins University.
More:
http://www.nytimes.com/2008/03/21/us/21vaccine.html