Last week, one of my friends posted this article on Facebook that started a lengthy discussion about safety of the Gardasil vaccine. Gardasil prevents several types of cancer and genital warts caused by the human papilloma virus (HPV). I know several girls and women who have had the vaccine, but I hadn’t heard anything controversial about it. An initial search found players from pro- and anti-vaccination sides fighting relentlessly and emotionally via social media and blog comments. Since most of the websites don’t exactly look reputable, I dove into some research about the topic. The article above was posted on March 3rd, 2014, but it is almost an exact replica of many articles that started appearing on various websites and media outlets in 2009 and still do (Find a few here, here and here).
Negative press about the vaccine appears to originate from a talk given by Dr. Diane Harper at the 4th International Conference on Vaccination in 2009. This conference is organized by the National Vaccine Information Center, who questions vaccine safety and identifies children at risk from adverse effects. The website claims to utilize science-based information to form their claims. However, one of their videos suggests that childhood vaccines contribute to unexplained chronic disease and disabilities, all which are not agreed upon by the scientific community. Dr. Harper was an employee at Merck, the company that makes the Gardasil vaccine. At the conference, Dr. Harper allegedly chose “to clean her conscience about the deadly vaccines so she could sleep at night,” and the anti-vaccination movement has cited her as a credible source for their cause. Dr. Harper’s talk has been miscomprehended and misquoted, and after the conference she has repeatedly clarified her statements. She does have reservations about how long the vaccine lasts and whether the vaccine would lead to a false sense of security, causing women to stop regular pap smears. However, Dr. Harper has expressed that she supports the vaccine and is not concerned about safety. After these clarifications, articles and various videos have considered whether she’s mentally ill, or if she was paid off by the vaccine company; thus, various conspiracy theories have thrived in the vaccine arena.
What anti-Gardasil articles have claimed and evidence for why they’re wrong:
Cervical cancer risk is already low and the vaccine is unlikely to have an effect.
Compared to incidence of other cancers, those caused by HPV are relatively low. However, these are cancers preventable with a readily available vaccine that has been proven effective. Cases of HPV have already decreased with the adoption of the vaccine (according to the CDC and American Cancer Society).
15,037 females reported side effects, including extremes like Guillian Barré syndrome, lupus, seizures, clots, and brain inflammation.
When a vaccine is licensed, the CDC continuously monitors and evaluates adverse effects with different systems. The HPV vaccine was released in 2006 and there have been several post-licensure studies. The Vaccine Safety Datalink performed a safety assessment of 600,000 doses of HPV vaccines administered to 9-26 year old female recipients from 2006-2009. They compared cases of serious adverse effects to historical background rates. They also compared common outcomes (allergic reactions, dizziness) to an unexposed adolescent group. None of the adverse effects were more common after administering Gardasil. In another study from 2006-2009, the Vaccine Adverse Event Reporting System revealed 12,000 adverse effects,92% of which were non-serious (fainting, nausea, headache, fever, pain at injection site). Most adverse effects were not greater than background rates. There were slightly greater reports for blood clots (VTE) after vaccination, but patients had known risk factors, so an association with the vaccine is not likely. The CDC continues to monitor the situation and according to a 2013 report, there are still no safety concerns. Further, studies in other countries have also found no associations between adverse effects and the vaccine.
44 girls have died from the vaccine.
According to the above scientific studies that assessed adverse effects, and CDC summaries, there is no indication that these deaths were caused by the vaccine (though videos like this run rampant). A correlation between two events does not necessarily mean that one caused another; this is a mistake that has been made over and over in the past. Read or watch here about a time when we were convinced that ice cream caused polio.
There’s no evidence that the vaccine prevents cancer.
According this FDA fact sheet, several studies showed that Gardasil “was nearly 100 percent effective” in preventing various effects of HPV, including precancerous cervical, vaginal and vulvar lesions and genital warts. Some of these studies, including Dr. Harper’s can be found here and here.
Most women will have HPV at some point in their lives and in 98% of the cases, it resolves on its own. So, why vaccinate at all?
While the majority of HPV infections do resolve on their own, there are 14 million new cases and 26,000 cases of cancer yearly attributed to HPV in the US. Though pap smears have been effective to catch problems at the early stages, they don’t prevent the development of cancer – Gardasil does. In addition, the vaccine prevents other effects from HPV like genital warts, providing the chance to improve the lives of many Americans. Indeed, the vaccine has decreased infection and cancer rates despite low vaccination.
Trials were performed with females aged 15 or older, but are marketed to younger girls.
Clinical trials prior to release of the vaccine were performed with children of the above age group. However, several post-licensure trials have studied 9-26 year old females, a wider range of ages than suggested in the article. The vaccine was effective and safe in those younger age groups.
Protection by the vaccine only lasts 5 years.
This was one of the biggest challenges Dr. Harper had for the vaccine and probably arose from this 5 year study. It is a valid concern; however, at the time of Dr. Harper’s talk in 2009, her own research article showed that the vaccine was effective for AT LEAST 6.4 years. Recent data has now shown it’s effective for AT LEAST 8 years. The reason the number keeps changing is because we are still studying how long the vaccine is effective. We only have so many years of data since the vaccine was licensed 8 years ago. The more years we have to study the vaccine, the more years we’re able to say the vaccine is effective until we have evidence to the contrary.
My bottom line: The Gardasil vaccine is currently safe and effective, though longevity is still being studied. In the US, about half a million people die every year from cancer, and our ability to prevent one cancer can make a big difference. I think the benefits of the vaccine outweigh minor side effects. This video is an engaging summary.
Despite evidence against adverse effects to Gardasil, vaccination has become a two-sided ‘us vs. them’ game. So, the next logical question might be: How does this misinformation persist?
I will discuss this later this week, so stay tuned!