There is currently a lot of fear about vaccines out there, and if you pay attention to the news, you’ve probably caught a whiff of it. This panic was launched by a 1998 Lancet article authored by Andrew Wakefield, who claimed that the MMR vaccine causes autism. Much ink was spilled unpacking that fiasco, but, in a nutshell, Wakefield falsified data and conducted unethical, invasive procedures on children, and was consequently stripped of his medical license. Researchers couldn’t duplicate his findings, The Lancet retracted his article, and Wakefield was thoroughly discredited.

One case report asserting a link between Gardasil and premature ovarian failure was authored by an anti-abortion activist.

But vaccine fears still linger. For example, there are some scary stories floating around about Gardasil, the vaccine that protects against the four most common strains of human papillomavirus (HPV), the sexually transmitted virus that can cause genital warts or certain types of cancer. These stories include claims that it has caused premature ovarian failure leading to infertility. About 57 million doses of HPV vaccines have been given in the United States, however, and in such a large group there are going to be some unexplained phenomena. Without good evidence, we can’t jump to the conclusion that a vaccine caused them.

According to the Centers for Disease Control and Prevention, the most common Gardasil side effects are fainting; dizziness; nausea; headache; fever; hives; and pain, redness, or swelling at the injection site. These reactions aren’t considered to be serious, most people don’t experience any of them, and they’re only temporary. However, while surfing the Internet or scrolling through your Facebook wall, you might have come across claims that Gardasil causes infertility — specifically, premature ovarian failure in girls and young women. What should you make of these horror stories?

A couple of medical journals have described unexplained ovarian failure in four patients who also received HPV vaccines. Medical journals publish many kinds of articles, and a “case report” is a description of one or a few patients’ experiences. Unlike an article that summarizes the results of a rigorous scientific study involving hundreds or thousands of subjects, a case report might just highlight an unusual situation. They aren’t considered to be sources of “definitive” statements about much of anything. Nevertheless, in 90 percent of patients with premature ovarian failure, doctors can’t find clear genetic or physiological causes for the condition, making it an interesting topic for a medical journal to cover — and ripe for speculation.

One case report, published last summer, discussed three patients who developed ovarian failure after receiving Gardasil. The article is behind a paywall, but surgical oncologist David Gorski excerpts from it liberally: The first patient had been experiencing irregular menstruation before receiving her first dose of Gardasil at age 14; that her periods stopped after completing the vaccination series is not evidence of a cause-and-effect relationship between the injections and menstrual problems. The second patient was the younger sister of the first, and completed the vaccination series when she was 13 years old. She did not get her first period until she was 15, but after two menstrual cycles, they stopped. Again, this isn’t clear evidence of a causal relationship, and it’s possible that two sisters could share genetic proclivities for menstrual problems. The third patient received all three Gardasil doses at the age of 21 and experienced menstrual irregularities a few months after the first dose, with her periods stopping two years later — again, no evidence of a causal relationship.

These three flukes might sound alarming when presented in isolation, but when put into the greater context, in which millions of Gardasil doses have been administered, they seem much more likely to be coincidental. In the United States, 1 out of 1,000 females experiences ovarian failure before the age of 30, and the overlap between this group and the Gardasil-receiving population makes it possible to cherry-pick cases and falsely assert cause-and-effect relationships. The authors attribute these cases to a condition they call “autoimmune/inflammatory syndrome induced by adjuvants,” which isn’t a generally accepted medical condition and in fact seems to have its roots in the anti-vaccination movement.

Another article, published in BMJ Case Reports, describes ovarian failure in a 16-year-old. The patient’s menstrual irregularities didn’t start until five months after receiving Gardasil, and her periods didn’t stop completely until more than a year after the last dose. There is no evidence that one thing had to do with the other — the authors merely speculate that it did.

The idea that Gardasil causes infertility probably arises from two misguided notions: (1) that Gardasil gives girls “permission” to be “promiscuous”; and (2) that promiscuity has sexual and reproductive consequences, in this case infertility. Firstly, studies have not found evidence to support fears of female promiscuity. For example, one study found no significant difference between the vaccinated and the unvaccinated in terms of number of sexual partners or the age at which sexual activity began. Secondly, the idea that disease is a punishment for our “sins,” rather than a consequence of genetics, microbes, environmental factors, or bad luck, is as old as the hills. Fear-mongering about Gardasil and infertility is just one manifestation of the idea that women deserve punishment for having sex.

By the way, the BMJ report’s lead author, Deirdre Little, who alleged that Gardasil caused ovarian failure in her teenage subject, is affiliated with the anti-abortion movement. She’s on the board of Family Life International Australia, whose website claims birth control pills cause abortion, vasectomy can lead to cancer, latex condoms don’t protect against HIV, and that Gardasil might be “part of the population control agenda.” In fact, Little reported on the 16-year-old girl’s case in the group’s newsletter.

More information about the HPV vaccine’s safety can be found at the CDC’s website. You can also find myths about HPV and Gardasil on our blog, as well as on Planned Parenthood’s website. Planned Parenthood health centers offer Gardasil and can talk to you about side effects. More information about the vaccine is available from Planned Parenthood and the National Cancer Institute.