Analysis Sexuality

One Dose of HPV Vaccine May Be Enough, Study Finds

Martha Kempner

A new study of women in Costa Rica finds that one dose of the HPV vaccine may be enough to create the antibodies needed to prevent infection. If confirmed, this could be good news for people in the United States and abroad.

A new study of women in Costa Rica finds that one dose of the human papillomavirus (HPV) vaccine may be enough to create the antibodies needed to prevent infection. If confirmed, this could be good news for people in the United States and abroad.

The study, funded by the U.S. National Cancer Institute and published in the November issue of Cancer Prevention Research, enrolled 503 Costa Ricans who fell into four categories. Some of the women (113) had antibodies to HPV because they had been infected with the virus. The others had received doses of the HPV vaccine Cervarix—78 of them had received just one dose, 192 had received two doses, and 120 had received all three.

The researchers compared the immune response of each of these groups by looking at the levels of antibodies in their blood. They found that up to four years later, women in all of the vaccine groups continued to have antibodies that would protect them from infection with HPV strains 16 and 18 (the two strains covered by Cervarix). Women who received just one dose of the vaccine had lower levels of antibodies than those who received all three, but the levels remained stable, suggesting that there was a lasting response. Women who received two doses six months apart appeared to have just as many antibodies as those who got all three. Also, women who received one dose and those who received two had antibody levels that were between five and 24 times higher than those of women who had never been vaccinated but were infected with HPV. The researchers believed these results suggest all three doses may not be necessary.

If confirmed, these findings will have the most impact in the developing world, where resources are scarce and cervical cancer rates high. Worldwide, more than 275,000 women die from cervical cancer each year (compared to about 3,900 in the United States). The vaccine costs about $130 per dose; if each woman needs fewer doses to be protected, more women can receive the vaccine for the same overall investment. As Mahboobeh Safaeian, the study’s author, noted to HealthDay, “Vaccination with two or even one vaccine dose could simplify the logistics and reduce the cost of vaccination in the developing world, where more than 85 percent of cervical cancer occurs and it is the most common cause of cancer death in women.”

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The results may also have an impact in the United States, where, as Rewire has reported, the HPV vaccine has been something of a tough sell. Despite the fact that an estimated 79 million people in this country are infected with HPV and the virus causes over 20,000 cases of cancer each year (cervical cancer as well as cancers of the head, neck, throat, genitals, and anus), parents seem reluctant to vaccinate their children. In 2012, the Centers for Disease Control and Prevention (CDC) found that only 53.8 percent of girls had initiated the vaccine series by getting the first shot, and even fewer (33.4 percent) had completed all three shots in the series. Moreover, a CDC survey of parents found that many did not intended to take their daughters back to complete the vaccination process. Though, clearly, we have to a better job of explaining the importance of the vaccine as well as the current recommendation that young people receive three doses, if one or two doses are sufficient, perhaps we could increase the percentage of girls who are protected.

A recent study in the United States also supports the theory that women are protected after fewer than three doses of the vaccine. As Rewire reported in June, a study published in the Journal of Infectious Diseases found the proportion of teen girls infected with the strains of HPV that the vaccine addresses has dropped by 56 percent since the vaccine was introduced. The study’s author, Lauri Markowitz, told the Washington Post that the results suggest those teens most in need of the vaccine’s protection were getting it, and that by preventing the virus in them, their peers were protected as well. She added that the fact protection seems to have set in even though so few teens in the United States have received the recommended three doses of the vaccine warranted further study and discussion about whether all three shots are necessary.

The authors of the current study also believe that additional research is necessary, in part because the Costa Rican study involved a relatively small sample of women. Moreover, that study looked at Cervarix, one of the two HPV vaccines available in the United States. The majority (99 percent) of young women who have received the vaccine here, however, have relied on the other brand name version, Gardasil, which appeared on the market first and protects against two additional strains of the virus.

Though this news is promising, until further research confirms it and guidelines change, parents and young women should continue to follow the current recommendations and obtain all three doses of the vaccine.

Roundups Sexual Health

This Week in Sex: The Sexually Transmitted Infections Edition

Martha Kempner

A new Zika case suggests the virus can be transmitted from an infected woman to a male partner. And, in other news, HPV-related cancers are on the rise, and an experimental chlamydia vaccine shows signs of promise.

This Week in Sex is a weekly summary of news and research related to sexual behavior, sexuality education, contraception, STIs, and more.

Zika May Have Been Sexually Transmitted From a Woman to Her Male Partner

A new case suggests that males may be infected with the Zika virus through unprotected sex with female partners. Researchers have known for a while that men can infect their partners through penetrative sexual intercourse, but this is the first suspected case of sexual transmission from a woman.

The case involves a New York City woman who is in her early 20s and traveled to a country with high rates of the mosquito-borne virus (her name and the specific country where she traveled have not been released). The woman, who experienced stomach cramps and a headache while waiting for her flight back to New York, reported one act of sexual intercourse without a condom the day she returned from her trip. The following day, her symptoms became worse and included fever, fatigue, a rash, and tingling in her hands and feet. Two days later, she visited her primary-care provider and tests confirmed she had the Zika virus.

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A few days after that (seven days after intercourse), her male partner, also in his 20s, began feeling similar symptoms. He had a rash, a fever, and also conjunctivitis (pink eye). He, too, was diagnosed with Zika. After meeting with him, public health officials in the New York City confirmed that he had not traveled out of the country nor had he been recently bit by a mosquito. This leaves sexual transmission from his partner as the most likely cause of his infection, though further tests are being done.

The Centers for Disease Control and Prevention (CDC)’s recommendations for preventing Zika have been based on the assumption that virus was spread from a male to a receptive partner. Therefore the recommendations had been that pregnant women whose male partners had traveled or lived in a place where Zika virus is spreading use condoms or abstain from sex during the pregnancy. For those couples for whom pregnancy is not an issue, the CDC recommended that men who had traveled to countries with Zika outbreaks and had symptoms of the virus, use condoms or abstain from sex for six months after their trip. It also suggested that men who traveled but don’t have symptoms use condoms for at least eight weeks.

Based on this case—the first to suggest female-to-male transmission—the CDC may extend these recommendations to couples in which a female traveled to a country with an outbreak.

More Signs of Gonorrhea’s Growing Antibiotic Resistance

Last week, the CDC released new data on gonorrhea and warned once again that the bacteria that causes this common sexually transmitted infection (STI) is becoming resistant to the antibiotics used to treat it.

There are about 350,000 cases of gonorrhea reported each year, but it is estimated that 800,000 cases really occur with many going undiagnosed and untreated. Once easily treatable with antibiotics, the bacteria Neisseria gonorrhoeae has steadily gained resistance to whole classes of antibiotics over the decades. By the 1980s, penicillin no longer worked to treat it, and in 2007 the CDC stopped recommending the use of fluoroquinolones. Now, cephalosporins are the only class of drugs that work. The recommended treatment involves a combination of ceftriaxone (an injectable cephalosporin) and azithromycin (an oral antibiotic).

Unfortunately, the data released last week—which comes from analysis of more than 5,000 samples of gonorrhea (called isolates) collected from STI clinics across the country—shows that the bacteria is developing resistance to these drugs as well. In fact, the percentage of gonorrhea isolates with decreased susceptibility to azithromycin increased more than 300 percent between 2013 and 2014 (from 0.6 percent to 2.5 percent).

Though no cases of treatment failure has been reported in the United States, this is a troubling sign of what may be coming. Dr. Gail Bolan, director of CDC’s Division of STD Prevention, said in a press release: “It is unclear how long the combination therapy of azithromycin and ceftriaxone will be effective if the increases in resistance persists. We need to push forward on multiple fronts to ensure we can continue offering successful treatment to those who need it.”

HPV-Related Cancers Up Despite Vaccine 

The CDC also released new data this month showing an increase in HPV-associated cancers between 2008 and 2012 compared with the previous five-year period. HPV or human papillomavirus is an extremely common sexually transmitted infection. In fact, HPV is so common that the CDC believes most sexually active adults will get it at some point in their lives. Many cases of HPV clear spontaneously with no medical intervention, but certain types of the virus cause cancer of the cervix, vulva, penis, anus, mouth, and neck.

The CDC’s new data suggests that an average of 38,793 HPV-associated cancers were diagnosed each year between 2008 and 2012. This is a 17 percent increase from about 33,000 each year between 2004 and 2008. This is a particularly unfortunate trend given that the newest available vaccine—Gardasil 9—can prevent the types of HPV most often linked to cancer. In fact, researchers estimated that the majority of cancers found in the recent data (about 28,000 each year) were caused by types of the virus that could be prevented by the vaccine.

Unfortunately, as Rewire has reported, the vaccine is often mired in controversy and far fewer young people have received it than get most other recommended vaccines. In 2014, only 40 percent of girls and 22 percent of boys ages 13 to 17 had received all three recommended doses of the vaccine. In comparison, nearly 80 percent of young people in this age group had received the vaccine that protects against meningitis.

In response to the newest data, Dr. Electra Paskett, co-director of the Cancer Control Research Program at the Ohio State University Comprehensive Cancer Center, told HealthDay:

In order to increase HPV vaccination rates, we must change the perception of the HPV vaccine from something that prevents a sexually transmitted disease to a vaccine that prevents cancer. Every parent should ask the question: If there was a vaccine I could give my child that would prevent them from developing six different cancers, would I give it to them? The answer would be a resounding yes—and we would have a dramatic decrease in HPV-related cancers across the globe.

Making Inroads Toward a Chlamydia Vaccine

An article published in the journal Vaccine shows that researchers have made progress with a new vaccine to prevent chlamydia. According to lead researcher David Bulir of the M. G. DeGroote Institute for Infectious Disease Research at Canada’s McMaster University, efforts to create a vaccine have been underway for decades, but this is the first formulation to show success.

In 2014, there were 1.4 million reported cases of chlamydia in the United States. While this bacterial infection can be easily treated with antibiotics, it often goes undiagnosed because many people show no symptoms. Untreated chlamydia can lead to pelvic inflammatory disease, which can leave scar tissue in the fallopian tubes or uterus and ultimately result in infertility.

The experimental vaccine was created by Canadian researchers who used pieces of the bacteria that causes chlamydia to form an antigen they called BD584. The hope was that the antigen could prompt the body’s immune system to fight the chlamydia bacteria if exposed to it.

Researchers gave BD584 to mice using a nasal spray, and then exposed them to chlamydia. The results were very promising. The mice who received the spray cleared the infection faster than the mice who did not. Moreover, the mice given the nasal spray were less likely to show symptoms of infection, such as bacterial shedding from the vagina or fluid blockages of the fallopian tubes.

There are many steps to go before this vaccine could become available. The researchers need to test it on other strains of the bacteria and in other animals before testing it in humans. And, of course, experience with the HPV vaccine shows that there’s work to be done to make sure people get vaccines that prevent STIs even after they’re invented. Nonetheless, a vaccine to prevent chlamydia would be a great victory in our ongoing fight against STIs and their health consequences, and we here at This Week in Sex are happy to end on a bit of a positive note.

Commentary Science

HPV Vaccines Are Working, So It’s Time to Stop Arguing About Them

Martha Kempner

A new study finds that HPV rates have plummeted in the last six years. Yet HPV vaccination rates continue to lag behind those of other vaccines, in part because of the stigma surrounding sexually transmitted infections.

According to a new study, human papilloma virus (HPV) rates have plummeted in the first six years vaccines against the virus have been available. Unfortunately, HPV vaccination rates lag behind those of other recommended inoculations, in part because of the stigma that stifles conversations around sexually transmitted infections.

Perhaps these new success rates—coupled with additional new research that reminds us of the possibility of non-sexual HPV transmission—will convince more parents to take advantage of this potentially life-saving vaccine.

HPV is actually a group of more than 150 related viruses, 40 of which are known to be sexually transmitted. Most types of the virus are thought of as low-risk, because they are unlikely to cause health problems. Nine types, however, have been identified as high-risk and are thought to be responsible for 99 percent of cervical cancers and a large portion of vulvar, vaginal, penile, anal, and oropharyngeal (a part of the throat) cancers.

Since 2006, there have been three vaccines against HPV developed and released on the market. The most recent, made available last year, was the most wide-ranging; it protects against the nine high-risk types of the virus.

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The vaccine is given as a series of three shots over eight months. The Centers for Disease Control and Prevention (CDC) recommends that boys and girls begin the series at age 11 or 12 in order to be sure that they are fully vaccinated before they become sexually active, but those who do not get the shots at that time can get them at any point before age 26. Experts estimate that widespread vaccination could prevent up to 90 percent of cases of cervical, anal, and genital cancer.

Though the research released last month uses data collected before the latest vaccine was available, the success of the original vaccine supports an optimistic outlook for the future prevention of HPV.

For the new study, which was published in the journal Pediatrics, researchers used data from the CDC’s National Health and Nutrition Examinations Survey (NHANES). They compared cervical and vaginal specimens from individuals ages 14-to-34 collected between 2003 and 2006—before the vaccine was available—with samples collected between 2009 and 2012, after the first vaccine was in use. They also used vaccination records from the latter group.

They found that 11.5 percent of young women ages 14-to-19 in the pre-vaccine group had one of the four types of HPV covered by the original vaccine. This dropped to about 4 percent in the group examined after the vaccine was available. Among those ages 20-to-24, the prevalence rate dropped from 18.5 percent to roughly 12 percent. There was no change among the oldest age group.

Overall, the study concludes, within six years of the vaccine’s introduction, HPV rates were down 64 percent among teen girls and 34 percent among women in their 20s.

Dr. Laurie E. Markowitz, lead author of the study, told the Guardian that results were better than expected.“The fact that we are seeing a larger decrease overall than what we expect given our coverage rates does suggest there may be some herd protection,” which occurs when a large enough portion of the population is vaccinated to slow the spread of the virus, she said. “There also may be effectiveness from less than a complete three dose series,” Markowitz continued.

Researchers anticipate that more people will continue to benefit from the vaccines. Markowitz told the Guardian, “As women who got the vaccine when they were younger age move into these older age groups, we should continue to see a continued decrease,” because they will not transmit the strains to anyone else as they become sexually active.

In addition, vaccination rates have improved since this data was collected. In 2009, only about 44 percent of girls had received one dose of the vaccine and only about 27 percent had received all three. By 2014, two-thirds of teenage girls ages 17 and under had received at least one of the three recommended doses of the HPV vaccine, and about 40 percent had received all three doses.

The CDC recommends that boys get the HPV vaccine as well, but vaccinations rates among boys have always been lower than those among young women—perhaps because when the vaccine was originally introduced, it was only suggested for girls, or perhaps because it is best known for preventing cervical cancer. But vaccination rates for boys have been on the rise as well. In 2014, roughly 42 percent of teenage boys ages 17 and under had received at least one dose of the vaccine: about 8 percentage points higher than the year prior.

Unfortunately, HPV vaccination rates still lag behind those of other recommended vaccines. For comparison, in 2014, about eight in ten teens ages 17 and under had received the quadrivalent meningococcal conjugate vaccines and roughly 87 percent had received the Tdap vaccine, which covers tetanus, diphtheria, and pertussis.

There are a number of reasons that HPV vaccination rates might be lower than others, including the fact that only two states and Washington, D.C. require the vaccine for school-aged children. By contrast, the Tdap vaccine is required in most states; meningitis vaccines are required in about half. Additionally, some parents may not have the resources or time to take their children to get a series of three vaccinations.

Not surprisingly, there still exists a discomfort with the sexually transmitted nature of HPV. Since, the HPV vaccine was introduced, there have been those who argue that vaccination will be seen by teenage recipients as permission to have sex, thereby increasing their risky behavior. This faction also argues that it is not necessary to inoculate young people against HPV because they can easily avoid it by just not having sex.

Numerous studies have found that HPV vaccines do not, in fact, turn young people into sex machines. A study last year from the United Kingdom, for example, found girls who have been vaccinated are less likely to engage in risky sexual behavior than those who have not. An earlier study in the United States found that teen girls who had been vaccinated were more likely to use condoms than their non-vaccinated peers. Other studies have found that young people’s perception of sexual risk and risk behaviors do not change after vaccination.

Perhaps a new article will take the wind out of the sails of the argument that teens should “just say no” to prevent HPV. The paper, cleverly titled “Penises Not Required,” reviewed 51 studies that found evidence of transmission through means other than penile-vaginal or penile-anal intercourse. Some of the studies reviewed found HPV DNA in the genital tract of female “virgins”—though the definitions of “virgin” varied widely among studies, and were based on respondents’ self-reported sexual activity. Other studies found HPV DNA in children who had not been sexually abused. Some studies focused on evidence of HPV DNA on medical equipment, toilet seats, and sex toys, and questioned whether this would be sufficient to transmit the virus. And others suggested the possibility of finger-to-genital transmission either from a partner or even from one’s own hands.

The researchers told Rewire in an email that their results have to be interpreted cautiously, as they do not provide proof of non-penetrative or non-sexual transmission. Nonetheless, the possibility that this virus can be transmitted without sex should help us rid the HPV vaccine debate of moralizing. As the researcher concludes in the article, “The distribution of HPV vaccines has been hindered, in part, by societal discomfort with the role of HPV in human sexuality. A fuller appreciation of the potential for non-sexual HPV transmission could help increase vaccine acceptance.”

The facts are simple. We have a vaccine that prevents cancer, it’s working, and that’s a major public health victory. It’s time to stop arguing about whether vaccinating kids against an STD is a good idea and start protecting everyone.

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