Is HPV usually harmless?

HPV stands for human papillomavirus. It is an extremely common virus that infects nearly all sexually active adults at some point in their lives. There are over 100 different strains of HPV, and most of them are considered low-risk and do not cause any health problems. However, there are some high-risk strains, like HPV 16 and 18, that can lead to cancer if left untreated. This article will examine whether HPV is usually harmless or if it poses serious risks to health.

What is HPV?

HPV is a sexually transmitted infection caused by the human papillomavirus. There are more than 150 known strains of HPV. Nearly all sexually active adults will get infected with at least one type of HPV at some point in their lives. HPV is primarily transmitted through sexual contact, including vaginal, anal, and oral sex. It can infect both males and females.

Some key facts about HPV:

Extremely common – Around 79 million Americans are currently infected with HPV, with about 14 million new cases each year.
Often asymptomatic – Most people who contract HPV never develop any symptoms or health issues.
Self-clearing – Approximately 90% of HPV infections are cleared by the body’s immune system within 2 years.

Persistence can cause problems – In a small percentage of people, an HPV infection persists and can eventually lead to cancer.
Preventable – Safe sexual practices and vaccination can prevent most HPV infections.

Low-Risk vs High-Risk Strains

One important thing to understand about HPV is that there are low-risk and high-risk strains.

Low-risk HPV strains, like types 6 and 11, do not cause cancer. They are responsible for about 90% of all HPV infections. Low-risk HPV can cause benign conditions like:

Genital warts
Recurrent respiratory papillomatosis (warts in the throat)

These growths are not usually a serious threat to health.

High-risk HPV strains, like types 16 and 18, can lead to cancer if they persist. About 13 high-risk HPV types have been identified. They may cause abnormal cell changes that over many years can turn into cancers of the:

Cervix

Vagina
Vulva
Anus

Penis
Mouth and throat

High-risk HPV types cause around 70% of all cervical cancers and a substantial fraction of other cancers. However, even infections with high-risk HPV do not always lead to cancer.

Most HPV Infections Clear Quickly

The majority of both low-risk and high-risk HPV infections are cleared from the body by its immune system within 1 to 2 years. According to the CDC:

About 90% of new HPV infections, including those caused by high-risk HPV types, clear or become undetectable within 2 years.
When a high-risk HPV infection persists for many years, it can cause cellular changes that progress to cancer.

So while high-risk HPV can sometimes lead to cancer, this occurs only in a small percentage of people with long-term infections. Most HPV cases are cleared quickly before cancer can develop.

HPV-Related Cancers

While most HPV infections are harmless, high-risk HPV types are responsible for 5% of all human cancers worldwide. The following HPV-associated cancers are most common:

Cervical Cancer

Nearly all cervical cancers (over 99%) are linked to high-risk HPV infection.

HPV types 16 and 18 cause about 70% of all cervical cancers.
Women infected with high-risk HPV are 15 times more likely to develop cervical cancer.
Cervical cancer is extremely rare in women who get routine Pap tests.

Regular cervical cancer screening allows early detection and treatment of precancerous lesions. HPV vaccination also helps prevent cervical cancer.

Oropharyngeal Cancers

HPV causes about 70% of cancers of the oropharynx (throat, tonsils, back of tongue).
HPV type 16 is responsible for most oropharyngeal cancers.

These cancers affect more men than women.
HPV-positive oropharyngeal cancers tend to respond better to treatment.

Anal Cancer

Around 91% of anal cancers are linked to HPV infection.

HPV types 16 and 18 are found in about 75% of anal cancers.
Anal cancer is more common in women than men.
HIV-positive individuals are at increased risk.

Vulvar and Vaginal Cancers

HPV causes around 75% of vaginal cancers and 65% of vulvar cancers.
High-grade precancerous lesions can be detected early with screening.

Penile Cancer

Over 60% of penile cancers are linked to HPV.

HPV types 16 and 18 are most common.
Routine circumcision helps lower risk.

So while most cases of HPV resolve without issue, HPV is responsible for a considerable cancer burden, especially cervical cancer. However, screening and vaccination help prevent most HPV-related cancers.

Who is Most at Risk of HPV-Linked Cancers?

Some factors put certain groups at higher risk of developing HPV-associated cancers:

Weak immune system – People with HIV/AIDS or taking immunosuppressant medication are at higher risk of persistent HPV and cancer.
Smoking – Smoking doubles or even quadruples cancer risk from HPV.

Older age – Most HPV cancers occur in people over 50 as persistent infections acquired earlier in life take decades to develop into cancer.
Multiple sexual partners – Having many partners increases chances of acquiring high-risk HPV strains.

While anyone sexually active can get infected with HPV, certain lifestyle factors modulate your individual risk profile.

Most Cervical Abnormalities Regresses

HPV infection can cause abnormal cellular changes in the cervix known as cervical dysplasia. There are different grades of cervical dysplasia:

CIN 1 (LSIL) – Mild dysplasia
CIN 2 (HSIL) – Moderate dysplasia

CIN 3 (HSIL) – Severe dysplasia and carcinoma in situ (CIS)

Without treatment, CIN 2 and 3 can sometimes progress to cervical cancer. However, even moderate to severe cervical dysplasia often regresses naturally:

About 43% of untreated CIN 1 lesions will regress within 2 years.

32% of CIN 2 lesions will regress in 2 years.
Even with CIN 3, about 32% of lesions will regress within 30 months.

So while cervical dysplasia requires follow-up and monitoring, even higher grade lesions often regress on their own without intervention in younger women.

HPV Vaccination

There are HPV vaccines that provide strong protection against infection from high-risk HPV types that cause cancer and genital warts.

HPV Vaccines

There are currently 3 HPV vaccines approved by the FDA:

Gardasil – Targets 4 strains including HPV 16 and 18.

Gardasil 9 – Targets 9 strains including 16, 18, 6, and 11.
Cervarix – Targets 2 strains, HPV 16 and 18.

The vaccines are over 90% effective at preventing infections and precancerous lesions caused by the HPV types covered.

Who Should Get Vaccinated?

The CDC recommends routine HPV vaccination for:

Preteens ages 11-12 years (can start at age 9).
Everyone up till age 26 if not vaccinated already.

Some adults ages 27-45 based on shared decision-making with a provider.

The vaccine works best when given before any exposure to HPV. Catch-up vaccination is recommended for older age groups.

Impact of HPV Vaccination

In the decade after the vaccine was introduced, the United States has seen:

71% reduction in HPV infections covered by the vaccine.
87% reduction in HPV-linked cervical dysplasia.
50% reduction in cervical cancer among women 20-24 years old.

Widespread vaccination can dramatically reduce the rates of HPV infections and cancers. However, vaccination rates remain suboptimal. Only 54% of adolescents in the US are up to date with the HPV vaccine series as of 2020. Higher coverage would maximize the vaccine’s cancer prevention benefits.

Safe Sex Practices

Using condoms consistently and correctly can lower your chances of getting infected with HPV:

Condoms provide a physical barrier that prevents skin-to-skin contact where virus transmission can occur.

One study found condom use lowered risk of cervical HPV by 70% in newly sexually active women.
However, condoms only protect the covered area so are less effective at preventing HPV transmission from genital skin-to-skin contact.

Having few or mutually monogamous sexual partners is also protective. While not 100% preventive, safe sexual practices like condom use are important for lowering HPV exposure.

Diagnosis and Screening

There is no routine HPV testing in men. However, women should get regular cervical cancer screening:

Pap test – Screens for cervical cell changes that may indicate dysplasia or cancer.
HPV test – Tests for the presence of high-risk HPV strains.

Recommended frequency – Pap every 3 years for women 21-29 years old. Pap and HPV test every 5 years for women 30-65.

Regular screening allows precancerous lesions and early stage cervical cancer to be identified so they can be removed or treated before developing into invasive cancer.

Anal Pap tests for those at high risk can detect early anal cell changes before cancer develops. There are no standard screening guidelines for other HPV-linked cancers.

Treatment of HPV Conditions

There is no specific treatment for HPV infections – most resolve spontaneously. However, treatments are available for HPV-related growths and dysplasia:

Genital Warts

Genital warts are treated by removing the lesions. Treatment methods include:

Chemical destruction with trichloroacetic acid, podophyllin, or imiquimod

Freezing lesions off with liquid nitrogen cryotherapy
Surgical removal by excision or laser
Prescription topical medications

Genital warts often recur even after treatment.

Cervical Dysplasia

Cervical dysplasia is managed based on the lesion grade and woman’s age:

CIN 1 – mild dysplasia is often monitored without treatment as many regress spontaneously.

CIN 2/3 – moderate to severe lesions can be surgically removed by LEEP or conization.
Younger women are more likely to be monitored, while excisional treatment is offered more readily to women over 25.

Treatment aims to remove precancerous tissue to prevent progression to invasive cancer.

HPV-Linked Cancers

Early stage cancers linked to HPV are treated with surgery, chemotherapy, radiation, or a combination of these. HPV-positive oropharyngeal cancers tend to respond better to treatment compared to cancers not caused by HPV. Access to screening and early intervention improves outcomes.

Prognosis and Complications

Nearly all HPV infections are cleared by the body without causing any complications or need for treatment. However, in a small proportion of people, HPV can lead to cellular changes that may progress to cancer over many years if left undiagnosed and untreated.

Potential long-term consequences if HPV-related conditions are not managed appropriately include:

Genital warts – continue to recur and grow larger/more numerous.
Cervical dysplasia – abnormal cells turn into invasive cervical cancer.
Anal/penile/vaginal dysplasia – develops into respective invasive carcinoma.

Oropharyngeal warts – grow large enough to obstruct breathing.

But screening and prompt treatment can prevent most cases of invasive cancer related to HPV. People with HIV or other immunocompromising conditions require close monitoring for HPV-linked cancers.

Conclusion

Most HPV infections are transient and cleared quickly by the immune system without causing any health problems. However, high-risk cancer-causing HPV types are responsible for 5% of human cancers. Persistent infection with high-risk HPV is the biggest risk factor for cervical cancer and plays a role in several other malignancies.

While screening, vaccination, safe sex practices, and prompt treatment of precancerous lesions prevent most serious outcomes, HPV should not be considered always harmless or low-risk. Certain groups are at higher risk for persistence of infection and cancer development, especially cervical cancer.

Public health efforts aimed at improving awareness, reducing stigma, and increasing HPV immunization rates are critical for cancer prevention. Although transient HPV infection is common and rarely an issue, don’t ignore symptoms of warts or unusual growths, particularly around the genitals. See your provider promptly for evaluation and management of any persistent HPV-related lesions.