[{"@context":"https:\/\/schema.org\/","@type":"Article","@id":"https:\/\/share-dev.upmc.com\/2025\/01\/hpv-vaccine\/#Article","mainEntityOfPage":"https:\/\/share-dev.upmc.com\/2025\/01\/hpv-vaccine\/","headline":"How Does the HPV Vaccine Work?","name":"How Does the HPV Vaccine Work?","description":"Most sexually active people will catch the human papillomavirus (HPV) at some point in their lives. The human body can clear many of these infections on its own, but some strains of HPV linger in the body. Doctors consider these strains “high-risk” because they stay in the body, gradually changing infected cells in ways that […]","datePublished":"2025-01-13","dateModified":"2025-05-09","author":{"@type":"Organization","@id":"https:\/\/www.upmc.com\/","name":"UPMC","url":"https:\/\/www.upmc.com\/","sameAs":"https:\/\/share-dev.upmc.com\/upmc\/","parentOrganization":"UPMC"},"publisher":{"@type":"Organization","name":"UPMC HealthBeat","logo":{"@type":"ImageObject","@id":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2019\/04\/UPMC-HealthBeat-Logo.png","url":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2019\/04\/UPMC-HealthBeat-Logo.png","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2024\/12\/GettyImages-1354226816.jpg","url":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2024\/12\/GettyImages-1354226816.jpg","height":867,"width":1999},"url":"https:\/\/share-dev.upmc.com\/2025\/01\/hpv-vaccine\/","about":["Living and Wellness"],"wordCount":1255,"articleBody":"Most sexually active people will catch the human papillomavirus (HPV) at some point in their lives. The human body can clear many of these infections on its own, but some strains of HPV linger in the body. Doctors consider these strains “high-risk” because they stay in the body, gradually changing infected cells in ways that can lead to cancer.High-risk HPV strains can cause the following cancer types:Anal.Cervical.Oropharyngeal (the back of the throat).Penile.Vaginal and vulvar.These high-risk HPV strains affect millions of Americans, causing cancer in many of them. According to the Centers for Disease Control and Prevention (CDC), high-risk HPV strain infections cause cancer in about 36,000 people each year.A 2021 study in Sexually Transmitted Diseases estimated the number of Americans who likely have HPV at a given time. The researchers determined that about 42 million Americans had a high-risk strain of HPV in 2018. They calculated that 13 million more would likely get a new high-risk infection that year.Fortunately, health care providers have a powerful weapon for fighting high-risk HPV and the cancers it causes. The HPV vaccine is a safe, effective way to prevent these cancer-causing infections before they occur.Understanding How Vaccines Work with the Immune SystemMost vaccines work by introducing a small amount of foreign material into your body. Your immune system recognizes this foreign material as a threat, but vaccines are specially designed not to make you sick.The vaccine triggers your immune system to mount a low-level response to the “threat.” Vaccines teach your body to recognize and prepare for threats before it has to fight them for real.Here’s how it works:Upon recognizing the threat, your immune system jumps into action. Its specialized cells begin making and releasing proteins called antibodies.These antibodies bind to the threat and mark it for destruction.Antibodies circulate in your bloodstream at low levels until they find a matching threat. Vaccines help your body build a memory bank of threats by making these antibodies before you’re sick.If you encounter the real virus in the future, your body is ready. It sends these antibodies to mark the foreign invader, with any luck, destroying it before it can multiply and spread.How Does the HPV Vaccine Work?Some vaccines use weakened or dead versions of the virus they fight. These weak or dead viruses trigger your immune response to make antibodies but don’t make you sick.The researchers who developed the technology behind the HPV vaccine knew they couldn’t use a whole HPV virus. Doing so could introduce cancer-causing proteins into the people they wanted to protect.Fortunately, they realized they could trigger the immune system with non-cancer-causing HPV proteins in noninfectious bubbles of protein and fats. The bubbles trigger a strong immune response without making patients sick or exposing them to cancer-causing proteins.How Effective Is the HPV Vaccine?Currently, Gardasil 9 is the only HPV vaccine brand used in the United States. It protects against seven high-risk strains of HPV that can cause cancers. (The other two strains it fights cause most genital warts.)In 2017, a large study in The Lancet reported on the efficacy and safety of Gardasil 9. The researchers collected data from over 14,000 women and people with vaginas from 18 countries. They chose to study female people between the ages of 16 and 26 because the HPV vaccine initially targeted this population.Gardasil 9 prevented new, “high-grade” diseases of the cervix, vagina, or vulva in 97.4% of people studied. It effectively stopped infection by all nine targeted strains of HPV. By preventing infections, the vaccine also blocked abnormal, precancerous cells from developing.Note: Merck & Co., Inc., the pharmaceutical company that makes and sells Gardasil 9, funded this study. However, the collaboration included researchers from research centers around the world, many of whom weren’t Merck employees. This arrangement helps offset concerns about possible conflicts of interest.Can I Still Get HPV if I’ve Had the Vaccine?In short, yes \u2014 but it’s complicated.Gardasil 9 effectively protects against nine strains of HPV. Two of these strains account for most causes of genital warts. The remaining seven are high-risk and cause most HPV-related cancers. However, the National Cancer Institute (NCI) estimates that there are over 200 unique HPV viruses.You can still catch an HPV strain that the vaccine can’t fight. Fortunately, most of these strains are unlikely to cause cancer. Of the 12 known high-risk strains of HPV, the HPV vaccine protects against seven.Additionally, remember that the efficacy study only included a subset of female people. All received the vaccine precisely on schedule. In the real world, people often miss vaccine doses or start the HPV vaccine series at older ages.People who get vaccinated later in life may have already had HPV. If the strain they had was high-risk, it may have already caused cellular changes in the body. The HPV vaccine doesn’t prevent this established strain from damaging cells.A 2023 systematic review identified a consistent trend across 17 research studies. All 17 found the HPV vaccine most effective among the youngest age groups ages 18 and under.Finally, the vaccine may be less effective in people with compromised immune systems. A 2022 analysis of systematic reviews identified medical conditions that reduce people’s response to many vaccines.This includes people who have:Certain blood cancers, such as leukemia.Liver cirrhosis.Poorly managed HIV.Received an organ or stem-cell transplant.How Long Does the HPV Vaccine’s Protection Last?The U.S. Food and Drug Administration (FDA) approved the original HPV vaccine in 2006 and the current version, Gardasil 9, just 10 years later, in 2014.Collecting data from vaccine recipients takes years. As a result, even the newest studies can’t measure the vaccine’s effectiveness beyond 10 years. Fortunately, the initial results from Merck and others are promising, including:Gardasil, the original HPV vaccine, protects recipients for at least 10 years.The current HPV vaccine, Gardasil 9, protects recipients for at least six years.Researchers have even less data on the protection period in certain groups. For example, the CDC didn’t recommend the HPV vaccine for males until 2011, and the FDA didn’t authorize Gardasil 9 for use in people over 26 until 2018.Clinical practices take time to adapt to the latest research recommendations. Researchers will need several more years to gather enough data on these groups and measure their protection windows.Regardless of your age, sex, or medical history, you can learn more about the HPV vaccine by speaking with your primary health care provider.SourcesCenters for Disease Control and Prevention. Reasons to Get HPV Vaccine. LinkCenters for Disease Control and Prevention. HPV Infection. LinkSexually Transmitted Diseases. Estimated prevalence and incidence of disease-associated HPV types among 15\u201359-year-olds in the United States. LinkNational Human Genome Research Institute. Antibody. Link.StatPearls. Physiology, Antibody. LinkNational Cancer Institute. The HPV Vaccine. LinkNational Cancer Institute. Human Papillomavirus (HPV) Vaccines. LinkU.S. Food and Drug Administration. Gardasil 9. LinkThe Lancet. Final efficacy, immunogenicity, and safety analyses of a nine-valent human papillomavirus vaccine in women aged 16-26 years: a randomised, double-blind trial. LinkNational Cancer Institute. HPV and Cancer. LinkCenters for Disease Control and Prevention. Cancers Caused by HPV. LinkHuman Vaccines & Immunotherapeutics. Human papillomavirus vaccine effectiveness by age at vaccination: A systematic review. LinkVaccines. Vaccination for the Prevention of Infection among Immunocompromised Patients: A Concise Review of Recent Systematic Reviews. LinkOpen Forum Infectious Diseases. Clinical and Public Health Considerations for HPV Vaccination in Midadulthood: A Narrative Review. LinkCenters for Disease Control and Prevention. Recommendations on the Use of Quadrivalent Human Papillomavirus Vaccine in Males \u2014 Advisory Committee on Immunization Practices (ACIP), 2011. Link"},{"@context":"https:\/\/schema.org\/","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"2025","item":"https:\/\/share-dev.upmc.com\/2025\/#breadcrumbitem"},{"@type":"ListItem","position":2,"name":"01","item":"https:\/\/share-dev.upmc.com\/2025\/\/01\/#breadcrumbitem"},{"@type":"ListItem","position":3,"name":"How Does the HPV Vaccine Work?","item":"https:\/\/share-dev.upmc.com\/2025\/01\/hpv-vaccine\/#breadcrumbitem"}]}]