Is the HPV vaccine effective for individuals who are already infected?
Mar 18, 2025
Source: Cainiu Health
Dr. Zhang Lu
Introduction
The human papillomavirus (HPV) vaccine is effective against HPV types to which an individual has not yet been exposed, but it is not effective against HPV types that an individual has already contracted. If a person is already infected with HPV type 58, the vaccine will not prevent infection from this type; however, it can still prevent infection from other types not yet encountered, such as HPV types 1, 2, 3, 4, and so on. It is important to understand one's infection status before vaccination and to comprehensively assess the necessity of vaccination.
Generally speaking, HPV refers to human papillomavirus. The effectiveness of the human papillomavirus vaccine on individuals who are already infected mainly depends on the infection type. If someone is infected with a type of human papillomavirus included in the vaccine, the vaccine typically offers no benefit for that specific infected type. However, for human papillomavirus types the individual hasn't yet been infected with, the vaccine may still provide preventive effects. A detailed explanation is as follows:
The human papillomavirus vaccine primarily works by inducing the body to produce neutralizing antibodies against specific human papillomavirus types. Since there are multiple subtypes of human papillomavirus, if an individual is already infected with a certain type included in the vaccine, the vaccine generally has no effect on that already-infected type, because the vaccine cannot directly act on already-infected cells and viruses.
For human papillomavirus types that an individual hasn't been infected with, the vaccine may still offer preventive benefits. For example, if a person is infected with human papillomavirus type 16, but the administered vaccine also includes other types such as human papillomavirus type 18, then the vaccine can still provide protection against other non-infected types like human papillomavirus type 8, helping prevent infection with these types of human papillomavirus and their associated diseases.
Therefore, before receiving the human papillomavirus vaccine, one should understand their personal situation and identify the infection type, then comprehensively assess whether vaccination is necessary. Additionally, proper post-vaccination care is needed, such as keeping the injection site dry and maintaining a balanced diet.
