As an unfortunate legacy of the now discredited Wakefield “study” in many areas of the country, it has become too common that parents are opting out of vaccinating their youngsters before entering kindergarten. The negative consequences for their children is obvious, but for the school and the community as a whole the results can be quite significant. While some parents are legitimately opting out of vaccinations for medical, religious or philosophical exemptions from vaccinating their children. In the cases where parents have a sincerely held religious belief that prohibits vaccinations, those beliefs need to be respected; that is the small minority of cases. Similarly some children must not be vaccinated, either because they have medical conditions or have had adverse reactions which contraindicate their receiving vaccinations. These children depend upon what is known as herd immunity to protect them against serious if not lethal cases of contagious but preventable diseases. To achieve herd immunity, a critical mass of the population must be vaccinated, usually about 95% depending on the illness being vaccinated against. At this level, disease transmission is contained because it cannot be transferred. Outbreaks of disease, however, can occur in areas where this threshold is unmet, and those individuals who are not vaccinated; e.g., the young, the immunocompromised, the medically vulnerable, or those who are vaccinated but for whom the vaccine is not working, all become at risk.
The study researchers state that it is known that immunization exemptions occur in geographic clusters. Some of the lowest vaccination rates are occurring in the northwest, including parts of Oregon, Washington, Idaho, and Montana. In fact, a public health official characterized Oregon as the “black hole” of religious exemptions. In 2011 5.6% of entering kindergarteners had religious exemptions, an increase of 2% from ten years ago.
As a result of these clusters, we are seeing outbreaks of disease. California is experiencing an outbreak of pertussis. Last year there were 7,297 known or suspected cases in the state, which is a fourfold increase from 2009. By 2010, the number of pertussis cases exceeded 9,000. It is clear how this is happening: in some Bay-area schools, more than 40% of students are unvaccinated. Marin County, which had 350 cases in 2010, has appeared to stem the outbreak by offering vaccination clinics and requiring all middle and high school students to have up-to-date vaccinations. Last November 900 Marin county residents were vaccinated, and only 10 new cases were reported in the first nine months of 2011.
A 2008 measles outbreak in San Diego began with an unvaccinated 7-year-old who picked up the disease in Switzerland before passing it on to an infant in the pediatrician’s office and three classmates. Overall, 11 unvaccinated children were infected. Another measles outbreak occurred in Indiana when two people with measles visited a crowded Super Bowl venue, resulting in 12 measles cases.
Parents have become anxious about vaccines as the result of the now-debunked Wakefield study, which purportedly found a link between vaccinations and autism. Even though the Lancet, which published the study, ultimately retracted it and deemed it fraudulent, and even though Dr. Wakefield went on to lose his license, some parents are still refusing to vaccinate their children out of fears of autism. Other parents object to the number of shots their children are receiving by kindergarten or to their side effects. Ultimately, however, parents who choose to not vaccinate their children are placing them at risk of developing diseases such as measles, which has a 90% infection rate in unvaccinated people.
The good news is that in some areas, vaccination rates have begun to increase, perhaps in response to the swine flu epidemic, in which vaccines were in short supply, even for high-risk groups, and horrified and panicked parents watched otherwise healthy children succumb to the disease. In 2010, the national rate of vaccinations for MMR was 91.5%, up from 90% in 2009 but still short of reaching the critical mass for herd immunity to be in place.
A companion piece to the Stadlin study in the Journal of Infectious Diseases chastises medical providers who are allowing unnecessary medical exemptions, which not only results in failing to protect those who cannot be vaccinated, but also serves to increase unnecessary anxiety about the safety of vaccines overall. The authors urge physicians to follow the vaccination recommendations from the Centers for Disease Control and Prevention, the American Academy of Pediatrics, and the American Academy of Family Physicians. To not vaccinate children undermines the efforts to control or prevent entirely these vaccine-preventable diseases. Clearly, visiting the pediatrician for those vaccinations needs to be returned to the back to school to-do list for parents. It is time for parents to rely on sound science and medicine to make decisions, not outdated and discredited studies that have unleashed significant harm from preventable diseases.
