Human Papillomavirus (HPV) is a widespread virus transmitted through intimate skin-to-skin contact. While many infections resolve on their own, certain types can persist and lead to health complications. The HPV vaccine is a primary preventative tool, which raises a question for those already sexually active: is the vaccine still beneficial after a possible or confirmed infection?
How the HPV Vaccine Works
The HPV vaccine operates by preparing the body’s immune system for a potential future viral encounter. It is a preventative, not a therapeutic, measure. The vaccine contains components that look like parts of the virus but cannot cause an infection. This exposure prompts the immune system to produce antibodies, which are proteins that can recognize and neutralize the actual virus.
This process gives the immune system a blueprint of specific HPV types before the body is exposed to them. If a vaccinated individual later comes into contact with one of these HPV types, their immune system is already equipped with antibodies to fight off the virus, thereby preventing an infection.
The Vaccine and Existing HPV Infections
The HPV vaccine cannot treat or clear an active HPV infection that is already present. Its design is prophylactic, meaning it works to prevent a new infection from occurring. Once the virus has entered the body’s cells, the vaccine’s preventative mechanism is no longer applicable to that specific viral type.
Because the vaccine stimulates an antibody response to block viral entry, it does not have a function for a virus already inside the cells. Therefore, for an individual with a confirmed infection, the vaccine will not help their body clear that particular strain. The immune response generated by the vaccine is geared toward future protection, not treatment.
Benefits of Vaccination After Exposure
A benefit of receiving the HPV vaccine, even after becoming sexually active, lies in the diversity of the virus. Human Papillomavirus is a large family of related viruses with many different strains. An infection with one strain of HPV does not confer immunity against the other types. The current vaccine protects against nine different types of HPV, targeting the strains most associated with cancers and genital warts.
It is highly unlikely that an individual has been exposed to all nine of the HPV strains covered by the vaccine. For this reason, vaccination is still recommended, as it can protect against the high-risk types they have not yet acquired. If a person is infected with one high-risk HPV strain, the vaccine can still provide protection against other cancer-causing strains and the types that cause genital warts.
This protection against multiple strains is a primary reason vaccination remains a valuable health measure. Even if a person already has HPV, the vaccine can help prevent new infections from other HPV strains included in the vaccine. Reducing the risk of acquiring additional high-risk HPV types lowers the long-term risk of developing HPV-related cancers.