In defense of vaccines

Monday night’s Tea Party debate inspired a myriad of articles, blog posts and tweets, largely from the health community, in response to Minn. Rep. Michele Bachmann's vehement opposition to Texas Gov. Rick Perry’s executive order for mandatory vaccination against the human papillomavirus (HPV) for girls entering the sixth grade.  Bachmann called the vaccine a potentially “very dangerous drug” and suggested that it has ties with mental retardation. 

Part of Bachmann’s attack on Perry is questioning the ethics behind his support for the vaccine. There are two vaccines that protect against HPV: Gardasil and Cervarix. Gardasil, made by pharmaceutical company Merck, is the more popular vaccine in the United States.  It is a quadrivalent vaccine, meaning it protects against four types of the virus. Cervarix is GlaxoSmithKline’s bivalent vaccine against HPV. Merck has reportedly given a total of $30,000 to Perry’s campaign since 2000.  Further, Perry’s former chief of staff worked for the pharmaceutical company, putting his motives for mandatory vaccination in question. What makes the Governor’s proclaimed concern for the well-being of young girls even more suspect is his inability to discuss why Texas has the third highest rate of teen pregnancy in the United States in a recent interview on a local television station. The governor lacked knowledge of the statistics and facts surrounding the issue. 

More concerning to the health community than the ethical questions is how Bachmann's incendiary remarks at the debate may have unnecessarily harmed the reputation of vaccines. 

Human papillomavirus

According to the Centers for Disease Control and Prevention (CDC), HPV is the most common sexually transmitted infection. The virus can infect genital areas, mouths and throats of both men and women. In roughly 90 percent of cases, the human immune system clears out the virus within two years.  Though it may seem like a relief to not have symptoms, appearing healthy is actually quite dangerous as an individual can pass on the virus without knowing it. In instances when the immune system cannot rid the body of the virus, genital warts, warts in the throat, and, albeit rarely, cervical cancer, cancers of the vulva, penis, vagina, anus and oropharynx can develop.  These cancers are rare, but they can be fatal.   

HPV can be transmitted through vaginal, anal and oral sex, or via genital-to-genital contact. It can also be transmitted from mother to infant. 

The CDC reports that approximately 20 million Americans are currently infected with HPV. Further, it is estimated that 6 million are infected annually and that at least 50 percent of sexually active men and women have it at some point. Out of the 12,000 cases of cervical cancer each year, almost all are HPV-related cases. 

Cervical cancer shows no symptoms until it has reached advanced stages, so cervical cancer screenings are recommended. Cervical cancer used to be one of the leading causes of female deaths in the United States, but due to increased screenings and vaccines, deaths from cervical cancer have decreased.

The CDC recommends vaccination as prevention for HPV and confirms that vaccines are most effective if given at 11 or 12 years of age. 

And now on to vaccines…

As Monday night’s debate may have hinted, the rate of vaccine refusal across the globe should be improved. In recent years, Europe has seen a significant increase in measles cases; France recorded nearly 5,000 cases in the first three months of 2011, compared to the 5,000 cases for all of 2010. To prevent disease outbreaks, a certain level of immunization must be maintained. According to the World Health Organization (WHO), vaccination rates in Europe fell below the recommended level, perhaps due to a fraudulent study later retracted, claiming a link between certain vaccines and autism. As a result of misinformation leading the people to reject safe vaccines, the health of the public suffered. 

The New England Journal of Medicine has explored the shift in perception regarding vaccine safety. Because of the success of vaccines in protecting the world from smallpox (the first disease to be eradicated), the perceived risk of these illnesses has decreased over the years and the perceived risk of harm from vaccines has taken its place;

“…the memory of several infectious diseases has faded from the public consciousness and the risk-benefit calculus seems to have shifted in favor of the perceived risks of vaccination in some parents’ minds,” writes Dr. Saad B. Omer et al. for the New England Journal of Medicine. 

Thus, contributing to the increase in vaccination refusal are two key factors: a false sense of security and a baseless fear of vaccines. 

How do Bachmann’s statements affect vaccinations?

There is a serious concern that Bachmann’s statements could have an adverse impact on vaccine uptake, particularly as the perceived risk for some infectious diseases has decreased in developed countries. 

Interesting work done by the Salathé Group at Penn State examines sentiments towards vaccines, how they cluster geographically and the impact of social media on these sentiments. Through disease transmission simulation they find:

“…if clusters of negative vaccine sentiments lead to clusters of unprotected individuals, the likelihood of disease outbreaks are greatly increased.”

What does all of this have to do with the Tea Party debate? An influential public figure questioned the safety of a recommended vaccine.  Thousands of viewers may take her word. 

The New England Journal of Medicine uses evidence from a study on measles cases from 1985-1992 to show that unvaccinated school children were 35 times more likely to get sick than those who received the vaccine. A second study provides evidence that the local community is more at risk for infection when there is a cluster of vaccine refusals.

Historically, there has been debate over mandatory vaccination. The tensions lies between individual rights and concern for public health. 

In 1905, in Jacobsen v. MA, the US Supreme court supported the rights of states to enforce compulsory vaccination, affirming that states have the power to make laws that are necessary to protect the public health and welfare. In 1922, the US Supreme Court found school immunization requirements to be constitutional. By the 1980’s, all 50 states had school immunization requirements. Shortly thereafter, more and more exemptions were permitted for medical, religious, personal and philosophical beliefs.

Monday night’s debate brought up concerns regarding ethics, state power in personal decisions, health and safety. It is true that the CDC recommended Gardasil in 2006 and not all long-term effects can yet be understood or evaluated. It is also true that the American Cancer Society and the American Association of Pediatrics recommend this vaccine and reject that it has any ties to mental retardation.

Vaccine legislation is tricky as it requires a balance between advocates for individual freedom and protection of community health.  All parties, however, should agree in principle that reckless claims and misinformation should have no part of these important discussions.