Human papillomavirus, or HPV, is a common virus that affects both males and females. There are more than 100 types of the virus. In fact, certain types of HPV cause common warts on the hands and feet. Most types of HPV are harmless, do not cause any symptoms, and go away on their own. Moreover, HPV may also be passed from mother to baby during labor and birth.

There are about 40 types of HPV that affect the genital area. Up to 80% of males and females who have had any kind of sexual activity involving genital contact will be infected with at least one type of genital HPV at some time. Most genital HPV infections do not cause any symptoms and people usually do not know they have the infection as their immune system clears the virus naturally. However, certain ‘high risk’ genital HPV types can sometimes lead to cancers of the cervix (Pic. 1), vulva, vagina, penis, anus, mouth and throat (Pic. 2).

The HPV virus is spread through direct skin to skin contact with an infected person, most commonly through sexual contact. The virus can be passed from person to person even if there are no visible warts. Warts that occur elsewhere on the body are caused by different types of HPV and contact does not seem to cause genital warts. If visible warts are treated as soon as they appear, the spread of HPV is reduced. The virus can live in the skin for many years and during that time can be passed on through sexual contact. Even though the warts are gone, HPV can still be living in the genital skin and it is still possible to transmit the virus to a partner. This explains why genital HPV infection spreads easily among sexually active people. It is unknown how long a person with HPV infection remains infectious or can pass the infection on to a sexual partner. Spermicidal foams, creams and gels have not been shown to have any effect against HPV.

Certain types of HPV affecting the cells in the cervix can be detected by cervical screening tests. HPV infection has the potential to cause cervical cancer if not treated, but this takes 10 to 15 years (Pic. 3). Most women clear the HPV infection without treatment or cancer.

The HPV infection itself cannot be treated. In most people, the virus is cleared naturally in one to two years. Treatments are only available for the genital warts and cancers caused by the infection.

Associated diseases

Cervical cancer

Most women who have HPV will clear the virus naturally and do not develop cervical cancer. In a small number of women HPV stays in the cells of the cervix. If the infection is not cleared, there is an increased risk of cervical cancer. It is important to have a cervical screening test every 5 years so HPV and associated cell changes can be identified, checked and treated if necessary.

Globally, HPV types 16 and 18 together account for more than 70% of the cervical cancer cases while the next most common oncogenic HPV types are 45, 31 and 33 and together account for about an additional 10%.

Despite its contribution to the development of cervical cancer, HPV is also associated with oropharyngeal (throat), vaginal, vulva and anal cancers. About 12% of cancers of the oropharynx and 3% of cancers of the mouth are attributed to HPV infection. However, the major risk factors for these cancers are tobacco use and alcohol consumption. The effects of these two risk factors are multiplicative.

Anal cancers

The HPV infection results in about 90% of anal cancers. The other risk factors to the development of anal cancers are HIV infection, cigarette smoking, anal intercourse and multiple sexual partners. 

HIV

The HPV infection and pathologies are both increased in HIV-positive individuals. The mechanism of interaction of HIV and HPV is not known but it may involve immune suppression rather than direct interaction.

Vaginal cancers

The vaginal intraepithelial neoplasia, which is a preinvasive disease of the vagina, has been associated with HPV infection. The vagina lacks a transformation zone, whereas in the cervix immature epithelial cells are infected with HPV. It has been theorized that the HPV entry mechanism involves abrasions from coitus and the use of tampons. The HPV may begin its growth in a healing abrasion in a similar fashion as in the transformation zone. The upper third of the vagina is vulnerable to the development of dysplasia and carcinoma in situ whether or not hysterectomy (surgical removal of the uterus) has been performed previously for intraepithelial neoplasia (abnormal growth of cells on the surface that could potentially lead to cancer). Each of these entities has a potential for progression to invasive cancer. For this reason, women who have had a hysterectomy with a history of HPV or intraepithelial neoplasia should continue to have periodic cytologic screening of the vaginal apex.

Vulvar cancer

The HPV infection is strongly associated in younger women with vulvar cancer. This is preceded with high-grade vulvar intraepithelial neoplasia which is commonly associated with high oncogenic type 16 and to a lesser extent type 18. Although the incidence of vulvar intraepithelial neoplasia and HPV has increased over the past decade, the incidence of vulvar cancer has remained relatively constant.

Genital warts

The non-oncogenic or low-risk HPV types can cause genital warts. The low-risk HPV types 6 and 11 are found in most of the genital warts. The HPV type 6 is most commonly detected in genital warts (about 90% of warts) followed by HPV type 11 (10–30% of warts). 

Complications

Pregnancy complications

Vertical (mother-to-child) transmission of HPV during pregnancy may be involved in the pathophysiology of preterm rupture of membranes and spontaneous preterm birth. In patients undergoing intrauterine insemination (IUI) for idiopathic (unexplained) infertility, HPV infection confers a lower pregnancy rate. In contrast, the evidence regarding any detrimental impact of HPV infection on in vitro fertilization (IVF) outcomes is inconclusive. It has been suggested that vaccination could potentially counter HPV-related sperm impairment, trophoblastic apoptosis (programmed cell death that occurs in trophoblast - a part of the placenta), and spontaneous miscarriages; however, these conclusions are based on in vitro studies rather than large-scale epidemiological studies. Improvement in the understanding of HPV sperm infection mechanisms and HPV transmission into the oocyte and developing blastocyst (early embryo stage) may help explain idiopathic causes of infertility and miscarriage.

Risk factors

  • acquisition of new male partners
  • an increasing number of lifetime sexual partners both in females and their male partners
  • having non-monogamous male partners
  • damaged skin
  • weakened immune system
  • to be born to infected mother

Regarding fertility, HPV seems to affect both men and women—the virus can bind to the head of a spermatozoon (motile sperm cell) and reduce sperm motility in men and may reduce the endometrial implantation of trophoblastic cells of placenta in women, thus increasing the theoretical risk of miscarriage. However, the role of HPV as a direct cause of infertility remains uncertain.

Female fertility

HPV shouldn’t affect patient’s ability to conceive. However, HPV has been linked with adverse pregnancy outcomes such as preterm rupture of membranes, spontaneous preterm birth, and a potentially increased rate of early pregnancy loss. 

Male fertility

In men, HPV infection can affect sperm parameters, specifically motility. Other semen parameters such as volume, viscosity, count, and morphology are not different in HPV-infected and in noninfected semen samples.

HPV-infected sperm can transmit viral DNA (genetic material) to oocytes, which may be expressed in the developing blastocyst (early embryo stage). HPV can increase trophoblastic apoptosis and thus theoretically increase the risk of early pregnancy loss.

Preventing the spread of HPV involves having safe sex, regular cervical screening tests and being vaccinated if eligible.

Safe sex

The use of condoms for sex is encouraged. Using condoms will reduce the spread of HPV but will not completely remove the risk. Spermicidal foams, creams and gels have not been shown to have any effect against HPV.

Cervical screening tests

Women aged 25 to 74 years should have a cervical screening test every 5 years to monitor the presence of HPV and any changes to the cells in the cervix. You may be sexually active before the age of 25; however the National Cervical Screening Program recommends screening commence at age 25.

Regular cervical screening tests are important for all females, whether vaccinated against HPV or not, as the HPV vaccine doesn’t protect against all types of HPV that can cause cervical cancer. As cervical screening tests detect HPV and abnormal changes to cells in the cervix, treatment can start before cancer develops.

Vaccination

Some types of HPV infection can be prevented. The vaccine protects against 9 types of HPV for more than 90% of uninfected women who are vaccinated. The vaccine protects against infection with the types of HPV which cause more than 70% of cases of cervical cancer. The vaccine will not prevent all types of HPV that cause cervical cancer.

The vaccine is given as a 2 or 3 dose schedule over a 6 month period (the Immunisation Provider will advise which schedule patient needs). The vaccine is most effective when all doses have been given. Missed doses should be given as soon as possible.

Immunisation is still recommended for people who have had sexual contact, even though they may have already been infected with 1 or more of the 9 types of HPV as the vaccine protects against all 9 HPV types. The vaccine should not be given during pregnancy but is safe for breastfeeding women.

HPV infection is generally diagnosed by the presence of visible warts in both women and men. However, many people exposed to the virus do not develop visible warts because their immune system keeps the virus under control. Therefore, HPV infection may be present without any signs. There is currently no blood test to detect HPV infection.

The incubation period of HPV ranges from 3 weeks to 8 months. Approximately 10–30% of women have spontaneous regression of HPV infection in 3 months; 90% of women are able to clear the HPV infection within 2 years. A subset of women (10–15%) does not mount a successful cell-mediated immune response and they remain persistently infected. These women remain at risk for developing high-grade disease and possibly cancer.

Diet

Consuming immune-boosting foods helps prevent or get rid of wart. These include foods high in vitamin C, probiotic foods, raw cheeses, kvass, kombucha and goat’s milk kefir or coconut kefir.

Antiviral herbs

Use of antiviral herbs to boost the immune system and inhibit viruses may support the prevention. It is recommended to consume antiviral herbs as herbal teas, infusions or herbal-infused oils.

The most commonly known antiviral herbs include elderberry, Echinacea, calendula plant, garlic, astragalus root, and others.

There is no cure for HPV infection; however treating visible warts as soon as they appear reduces the spread of the virus. Warts are more difficult to treat in a person with an impaired immune system.

Pharmacotherapy

Treatment options include creams such as podophyllin, imiquimod, and trichloroacetic acid. 

Surgical therapy

Cryotherapy (using freeze) or surgery may also be an option. After treatment warts often resolve within 6 months. Without treatment, in up to a third of cases they resolve on their own.

The role of HPV in the success of assisted reproduction is less clear-cut; several studies show a decreased pregnancy rate for intrauterine insemination and in vitro fertilization in women with HPV compared to controls, while other studies show no correlation. 

Intrauterine insemination (IUI) as a type of artificial insemination involves the placement of sperm directly into the uterus at the time of ovulation, either in a natural menstrual cycle or following ovarian stimulation. The process allows the concentration of sperm in a small volume of culture media and then the concentrated sperm is placed into the uterus through a transcervical catheter. IUI has the advantages of being less invasive and more affordable than other assisted reproduction techniques such as IVF. IUI theoretically allows a relatively higher number of motile sperm to reach the oocyte. 

IVF and assisted reproductive technologies (ART) generally start with stimulating the ovaries to increase egg production. Most fertility medications are agents that stimulate the development of follicles in the ovary. Examples are gonadotropins and gonadotropin releasing hormone. After stimulation, the physician surgically extracts one or more eggs from the ovary, and unites them with sperm in a laboratory setting, with the intent of producing one or more embryos. Fertilization takes place outside the body, and the fertilized egg is reinserted into the woman's reproductive tract, in a procedure called embryo transfer.

Find more about related issues

Sources

Artificial insemination ―sourced from Wikipedia licensed under CC BY-SA 3.0
Human Papillomavirus (HPV) ―sourced from Queensland Government licensed under CC BY 3.0 AU
Human papillomavirus infection ―sourced from Wikipedia licensed under CC BY-SA 3.0
Genital wart ―sourced from Wikipedia licensed under CC BY-SA 3.0
Intrauterine insemination ―sourced from Fertilitypedia licensed under CC BY-SA 4.0
Genital HPV infection incidence graph ―by Retroid licensed under CC0 1.0
HPV causing cervical cancer ―by Manu5 licensed under CC BY-SA 4.0
Throat Warts - HPV ―by GalliasM licensed under CC BY-SA 4.0
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