Are vaccination exemptions a threat?

(This posting was updated with Minnesota data at 2:51 p.m.)

The New York Times reported today on the increasing disinterest of some parents in having their children vaccinated, in the belief that mercury and other ingredients in vaccines increase the risk of autism and other illnesses.

Says the Times:

The exemptions have been growing since the early 1990s at a rate that many epidemiologists, public health officials and physicians find disturbing.

Twenty-one states have exemptions to laws requiring children be immunized. Minnesota is one such state by virtue of this clause in the state’s immunization law:

If a notarized statement signed by the minor child’s parent or guardian or by the emancipated person is submitted to the administrator or other person having general control and supervision of the school or child care facility stating that the person has not been immunized as prescribed in subdivision 1 because of the conscientiously held beliefs of the parent or guardian of the minor child or of the emancipated person, the immunizations specified in the statement shall not be required. This statement must also be forwarded to the commissioner of the Department of Health.

The Times’ story says a big jump in the number of parents invoking their exemption has health officials worried that more kids running around without being immunized, threaten to reinvigorate illnesses — measles, for example — that have been declining as health threats. In the states that allow exemptions, according to the Johns Hopkins Bloomberg School of Public Health, the number of children whose parents invoked a personal-belief exemption rose from 1 to 2.54 percent between 1991 and 2004.

The situation in Minnesota is less clear, however. A spokesman for Johns Hopkins told MPR this afternoon that researcher Saad Omer, who provided the statistic to the Times, did not have a state-by-state break down. A spokesman for the Minnesota Department of Health says he is attempting to find out if there is such a record.

Minnesota Department of Health spokesman Buddy Ferguson says the percentage of parents claiming the exemption was .2 percent in 1992 and 1.27 percent in 2001. The methodology for the survey changed, making comparisons with earlier data difficult. The most recent data (2006) shows 1.23 percent for K and 7th grade combined and 1.32 percent for kindergarten only. The earlier numbers appear to be blow the natiional average mentioned in the Times story.

Even without the increase of personal-belief exemptions, the number of children without vaccinations is significant among certain groups in Minnesota.

The Minnesota Department of Health has identified several disparities. Children who live in low-income areas are under-immunized. Childhood immunization levels are as low as 45% in some low-income zip code areas of Minnesota; high-risk children are behind on hepatitis B vaccine; native American children are at increased risk of hepatitis A; and minority persons 65 years of age and older have low immunization rates, the department says.

Despite the article’s implications, however, the exemptions don’t seem to have local health officials especially worried. “We have not taken any active position on it (exemptions) and it would not be something the Mayo Clinic would do,” Dr. Denis Cortese, the president and CEO of the Mayo Clinic, told the National Press Club luncheon today. “We have a situation here where education and more knowledge and bringing people along is really the key, I think, to make this work. There are some legitimate concerns that people have about vaccines and this is where science and research can help quell that… Who knows what the truth is; we should be looking at this pretty hard.”

Had he just raised the possibility that vaccines do cause autism? Given the chance to explain his position again, Cortese said there’s no evidence to suggest they do.