Why did I still get infected with HPV after receiving the 9-valent HPV vaccine?

Even after receiving the 9-valent HPV vaccine, it is still possible to become infected with HPV due to factors such as the vaccine's limitations, pre-existing infection before vaccination, or unsafe sexual practices. Appropriate measures should be taken based on specific circumstances. The details are as follows:

1. Vaccine limitations

The 9-valent HPV vaccine is a preventive vaccine that protects against nine types of HPV. However, because there are many different types of HPV, the vaccine cannot provide 100% coverage. Therefore, if the HPV type one contracts is not among those targeted by the 9-valent vaccine, infection may still occur.

2. Infection prior to vaccination

The 9-valent HPV vaccine only provides preventive protection. After vaccination, it stimulates the body to produce antibodies, so that upon re-exposure to the virus, an immune response occurs, thus preventing infection. However, if a person was already infected with HPV before vaccination, the vaccine does not have therapeutic effects and therefore may result in apparent vaccination failure.

3. Unsafe sexual practices

The 9-valent HPV vaccine does not completely prevent HPV infection. If unsafe sexual behaviors continue after vaccination, or if one engages in sexual contact with an infected partner, the virus may enter through damaged mucosal tissue in the vagina and lead to HPV infection.

In addition, other contributing factors may include weakened immunity, prolonged time since vaccination, or incomplete vaccination series (not receiving all required doses). It is recommended to maintain good personal hygiene and undergo regular gynecological examinations.