Introduction Diseases caused by human papillomavirus (HPV) have become a global public health problem, and currently the only prevention method in the world is vaccines. The nine-valent HPV vaccine is the latest HPV vaccine that can prevent nine high-risk types of HPV infection, but whether it can protect us for life remains to be explored. Research Progress on Long-term Immune Sustainability The immunogenicity and protective effect of the nine-valent HPV vaccine have always attracted much attention, because only long-term studies can prove whether it can provide lifelong protection. So far, the results of a number of long-term immune persistence studies have been