Oh, they're common...But the incidence should be decreasing...
Genital warts, also called anogenital warts, are the symptoms of human papillomavirus (HPV) infection, the most common sexually transmitted infection (STI) worldwide.
It has been well-documented that having a single sexual encounter with someone infected with HPV carries a 65% chance of contracting the infection (1).
Once infection occurs, symptoms (genitals warts) tend to appear on average anywhere from 3 weeks to 8 months after the initial contact with an infected individual.
Keep in mind that there are over 100 types of HPV and only some are associated with genital warts. HPV-6 and HPV-11 are the types most commonly associated with genital warts (2). More specifically, these two types are found in over 90% cases of genital warts (3).
On average, the incidence of anogenital warts in women is 120.5 per 100,000, and for men 137 per 100,000.
One scientific analysis estimates that genital warts occur in up to 0.23% of the general population (4). When limiting the population to persons 15 to 49 years of age the incidence of genital warts increases to 1%.
Genital warts are associated with a very poor quality of life. Not surprisingly, most individuals choose to treat the warts instead of waiting for them to regress spontaneously.
The future appears bright
Since about 90% of genital warts are caused by HPV types 6 and 11; and the fact that a quadrivalent HPV vaccine covers HPV types 6, 11, 16 and 18, it is very ilkely that the incidence of genital warts will significantly decrease over the next decade or two. At least in the populations who receive the quadrivalent vaccine.
A person infected with a type of HPV that’s not associated with genital warts may be completely asymptomatic and unknowingly be infecting others with the virus.
In fact, about 90% of all HPV infections are asymptomatic (5).
Some may say,
So what if I become infected with an asymptomatic HPV?
This is a reasonable argument, but unfortunately some asymptomatic HPV infections (HPV types) carry a substantially higher risk of cancer. Cancer types include: cervix, throat, penis, and a few more.
Prevalence of HPV, or in other words the number of individuals infected with the virus at any given point in time, varies throughout the world.
Regions of the world with the highest HPV prevalence, include (6):
- Sub-Saharan Africa – 24% of the general population
- Eastern Europe – 21% of the general population
- Latin America – 16% of the general population
It is estimated that nearly 80 million Americans are infected with one of the over 100 types of HPV. Another 14 million contract the infection annually.
49% of these new infections occur in persons 15-24 years of age. This clearly shows that teens and young adults are at significantly higher risk of contracting the infection than the general population.
Fortunately, the rate of new infections has been gradually dropping over the past decade as a result of the introduction of an HPV vaccine.
All warts are not the same…
There are 4 main types of genital warts:
- Condylomata acuminata – moist skin
- Flat warts – moist skin
- Papular warts – keratinized skin
- Keratotic warts (lesions) – keratinized skin
But wait, there’s more!
Besides the (relatively benign) genital warts, HPV may cause, in very rare cases, malignant Buschke-Lowenstein tumors. These tumors affect the skin and mucosa of the genital tract and generally carry a poor prognosis. The exact etiology of these lesions is unknown and the treatment is still controversial, but usually involves surgical excision.
Anogenital warts in children
Development of anogenital warts in a child may indicate child abuse.
However, there are other possible causes of HPV infection in a toddler or an older child (7).
- Infection taking place during birth
- Skin-to-skin contact with an infected individual
Genital warts are nearly always associated with HPV infection, but not all HPV infections carry the risk of anogenital warts. Furthermore, the introduction of quadrivalent vaccine is likely to reduce the number of genital warts in the years to come.