Reflections on Vaccines and Autism
The December legislative hearing on vaccines and autism in Tupelo was informative and thought-provoking. I attended for professional as well as personal reasons. As a pediatrician, I have several patients who bravely contend with being “neuro-atypical”. I also am an old-enough physician to have seen too many children die
of diseases we now prevent with vaccinations. I have a long-standing high-frequency hearing loss and a constant ear-ringing that may well be due to childhood encounters with either measles or mumps. As an intern, I caught Hepatitis B trying unsuccessfully to save the life of a 6 week-old bleeding to death from what turned out to be Hepatitis B liver failure. I am a grandfather who earnestly hopes all of his grandchildren receive all of their immunizations on the currently recommended schedule and that they are never needlessly exposed to vaccine-preventable diseases in a waiting room.
At the hearing, several issues surfaced that deserve comment. First, who should
be granted the status of “expert” in an issue that could have major public health
implications? It is risky to accept testimony from someone who begins with “In my
thexperience with _X_ number of patients, ….” Since the early 20 Century, modern
medicine has attempted to focus on well–designed scientific studies as a basis for
treatment. Basing treatment decisions on “my vast experience” can be dangerous or fatal to patients. For example, pediatricians once confidently recommended aspirin to children until careful epidemiological studies in the early 1980s linked that commonly used medicine to a horrific childhood disease called Reye’s Syndrome. We stopped routinely using aspirin in children, and Reye’s syndrome disappeared. In the early 1990s, other
research suggested that it was safer for babies to sleep on their backs than their stomachs. Until that time and based on years of “experience”, most pediatricians had been advising families that stomach-sleeping was far safer. Again, medicine followed the science even though doing so flew in the face of our collective “experience”. As a result, the incidence of Sudden Infant Death Syndrome instantly was cut in half and thousands of children are alive today due to this intervention. Public health policy needs to be based on evidence-based data, not experience-based.
Is there valid evidence that vaccines cause autism? Succinctly stated, evidence
from large epidemiological studies routinely absolves vaccines. As one example, the lead article in the November 7, 2002 New England Journal of Medicine is a study of every
child born in Denmark from January 1991 to December 1998, some 537,000 children.
(Interestingly, the association of aspirin and Reye’s Syndrome was made with only 23 patients.) Eighty-two percent received MMR vaccine and eighteen percent did not. The risk of developing autism was no different in the two groups, and the onset of autism in the vaccinated children bore no relationship to when they received the MMR.
Which children should be granted medical exemptions and who should be allowed to grant them? Vaccines rarely can have significant complications (but
complications from the vaccine are far rarer that complications from the disease). Any child with significant complications within a clearly defined timeframe deserves an exemption. Children whose parents fear vaccines based on flawed science should not be granted exemptions, from my point of view. Those same parents would understandably want to bring their children in for care if they acquired a vaccine-preventable disease. Expecting other parents to vaccinate their children to protect non-vaccinated children with “herd immunity” and then exposing other parents’ children to receive care for a non-
immunized infected child is wanting it both ways and is unfair. One parent at the hearing asked why we license a physician and do not take a recommendation from him. Technically, I am licensed by the state to practice medicine and surgery. No hospital would grant me privileges so broad. Public health policy is too important to overrule it on the whim of any willing MD (or any other type of provider the legislature may consider) who wants to act compassionately but without expertise.
Are vaccine-preventable diseases still a public health threat? Consider
measles. Measles is a frightening disease. Before vaccinations, the U.S. yearly had an estimated 4 to 5 million cases (CDC data). Of these, 150,000 developed pneumonia
(currently, pneumonias with influenza are increasingly caused by dangerous extensively-drug-resistant bacteria and we could expect the same with measles), 48,000 were hospitalized, 1000 to 4000 developed encephalitis, and 400 to 500 died. Worldwide, there were an estimated 750,000 deaths (90% in children under 5) from measles in the year
2000 (WHO data). Massive immunization programs reduced the estimated deaths to 197,000 in 2007. There have been two measles importations into Tupelo since 1987. In that year, a teenager from Mexico visiting relatives here came to my office with measles. (The day before, he also had visited football practice at Milam Junior High. This resulted in a school-wide re-vaccination for measles, including one of my children.) Two weeks later, a nine-month old infant from Iuka who had been in the exam room across the hall from the Mexican teen came back with measles. Thankfully, to my knowledge, no further
cases occurred. (Interestingly, immunization programs in Mexico have now virtually eliminated endemic cases. All of this year’s US cases have come from Europe, Africa,
and Asia.) The second importation occurred a few years ago. That patient was a student at Covenant College in Chattanooga and was not vaccinated due to a religious exemption. During summer break she visited her missionary parents in Africa. She developed a fever just before she flew back from Africa through Europe to the US. She then took a commuter flight to Tupelo for a wedding. Because she was getting sicker, she was brought to NMMC Emergency Department. She was admitted to the hospital and subsequently diagnosed with measles. Again, to my knowledge, no further spread occurred. What prevented these two public health scares from becoming serious outbreaks was the high vaccination status of the population.
Are we seeing any consequences from relaxed vaccine policies nationwide? Interestingly, there is an ongoing “natural experiment” in the U.S. that gives us some insight into the risks of reduced vaccine coverage. All states allow medical exemptions in some form from vaccinations. Forty-eight states currently allow religious exemptions. Twenty of these 48 states also allow philosophical exemptions to vaccines. These 20 “dual-exemption” states can be considered “canaries in the mine” regarding the risk of return of vaccine-preventable disease. Indeed, exemptions roughly triple to 3 or 4 percent of children when dual-exemption states are compared to single-exemption states (CDC data). Again, consider measles. From 2000 to 2006, there was an average of a bit over 50 cases a year (including 2 deaths, evidence this is not a minor illness). In 2007 there were 116 cases. Through November 2008 there were 131 cases. There were actually fewer measles-infected non-residents (8) who brought measles into the US this year than in past years. (To compare, nine unvaccinated Americans traveled abroad and brought measles back.) Therefore, the vast majority of the measles cases this year came from secondary spread within the US. Nineteen percent of these “spread cases” were in infants too young to have received MMR. Many of these children were exposed in health care settings where infected children were taken for care. Of the 95 non-immune patients old enough to be vaccinated, 63 were unvaccinated due to religious or philosophical objections. Half of the 2008 cases occurred in Illinois (32) and New York (27), major international air-travel points of entry. Virtually all of the remaining cases, (63) occurred in nine of the twenty “dual-exemption” states – Arizona (14), Arkansas (2), Louisiana (1), Michigan (4),
Missouri (1), New Mexico (1), California (14), Washington (19), and Wisconsin (7). No cases were reported in Mississippi and West Virginia.
Is information on vaccine toxicity being hidden from the public? One parent
at the hearing stated that there was evidence on the CDC website detailing 2000 deaths from varicella vaccine. This is an extensive website, but I have been unable to find that information there or on the HHS, NIH, FDA, or AAP sites. The closest I could come was a “serious occurrence” rate of 22 reports per million doses of varicella vaccine given. (These reported occurrences are often not due to the vaccine.) Forty-eight million doses of vaccine were given between 1995 and 2005. Assuming that all reports were due to the vaccine, that would translate into about one thousand serious events over 10 years. To put this in perspective, before 1995, one child in ten with chicken pox was sick enough to visit a doctor. In the years before vaccination, over 1000 persons would die of chicken pox over a ten year period. Since vaccinations began in1995, yearly chicken pox deaths
have dropped an average of 78%.
Autism is deserving of the attention it is receiving. Anything that can be done safely to reduce its incidence is desirable. We should not, however, in the name of compassion, begin to disassemble our public health vaccine policy without overwhelming evidence it would help. That evidence is still lacking.
By Dr Charles Robertson, Jr. MD