The domestic applicable population of imported nine-valent HPV vaccine has expanded. Can we fight again after four-valent？

　　BEIJING, Aug. 31 (Zhongxin Finance reporter Zhang Ni) On the 30th, the micro-signal of "Merck China" announced that the new indication of its nine-valent human papillomavirus vaccine (nine-valent HPV vaccine) had been approved by National Medical Products Administration, China, and this approval marked the expansion of Merck’s nine-valent HPV vaccine to women aged 9-45 in China.

　　As soon as the news came out, it attracted great attention from the outside world. Merck’s vaccine was approved for listing in China in 2018, but at that time its applicable age group was women aged 16-26. "Being too old to be vaccinated" has always been a pain point for many women.

　　Then, the age range of vaccination has been broadened. Can people who have already been vaccinated with bivalent or tetravalent vaccines be vaccinated with nine-valent vaccines again? What is the effect after vaccination?

　　What are the functions of nine-valent HPV vaccine?

　　What is the function of nine-valent HPV vaccine? According to the information released by China Center for Disease Control and Prevention, the vaccine is suitable for preventing the following infections or diseases caused by HPV types contained in the vaccine:

　　One is the infection caused by HPV6, 11, 16, 18, 31, 33, 45, 52 and 58;

　　Second, precancerous lesions or atypical lesions caused by the above nine HPV types, including cervical intraepithelial neoplasia (CIN) grade 2/3, cervical adenocarcinoma in situ (AIS) and cervical intraepithelial neoplasia (CIN) grade 1;

　　The third is cervical cancer caused by HPV16 types 16, 18, 31, 33, 45, 52 and 58.

　　What are the main differences between bivalent, tetravalent and nonavalent vaccines, and how to choose them?

　　The main difference between bivalent, tetravalent and nonavalent HPV vaccines is that they contain different HPV types. Bivalent HPV vaccine contains L1 proteins of HPV types 16 and 18, tetravalent HPV contains L1 proteins of viruses 6, 11, 16 and 18, and nonavalent HPV contains L1 proteins of viruses 6, 11, 16, 18, 31, 33, 45, 52 and 58.

　　However, all three vaccines can target the above-mentioned high-risk HPV, prevent HPV-related diseases, and all can fight HPV16 and 18 infections, and the effect is very significant. Compared with bivalent HPV vaccine, tetravalent HPV vaccine can also prevent genital warts caused by HPV6 and 11, and the nine-valent HPV vaccine will increase the proportion of preventing cervical cancer from 70% to 90%.

　　I have already vaccinated bivalent and tetravalent vaccines, can I still fight for nine?

　　At present, people are most concerned about whether bivalent and tetravalent vaccines can be vaccinated in the future. Is it necessary?

　　In this regard, CDC has said that there is no clinical data to support the interchange of nine-valent HPV vaccine with other HPV vaccines. The World Health Organization’s position paper on HPV vaccine has no preference for three vaccine recommendations.

　　From the public health point of view, bivalent, tetravalent and nonavalent vaccines can provide considerable immunogenicity and protective efficacy in preventing cervical cancer (mainly caused by HPV16 and HPV18). According to the existing conditions, it is possible to inoculate any of the three HPV vaccines.

　　According to the instructions of the nine-valent HPV vaccine, if someone wants to vaccinate the nine-valent HPV vaccine after three doses of the four-valent HPV vaccine, they can only be vaccinated at least 12 months later, and the inoculation dose is three doses.

　　Can I get a bivalent or tetravalent vaccine after one or two shots?

　　China CDC has previously introduced that in 2016, the Advisory Committee on the Implementation of Immunization Strategy (ACIP) recommended that if the vaccination procedure was started with tetravalent or bivalent HPV vaccine, the remaining doses could be replaced with nine-valent HPV vaccine to complete the whole vaccination procedure, but according to the World Health Organization’s 2017 position paper on HPV vaccine, the information about the safety, immunogenicity or effectiveness of the interchangeable use of the three HPV vaccines is very limited. These vaccines are different in characteristics, components and indications; In addition, the instructions for the use of tetravalent and nonavalent HPV vaccines also specifically pointed out that there is no clinical data to support the interchangeable use of nonavalent HPV vaccines with other HPV vaccines.

　　Therefore, in areas where multiple vaccines can be selected, efforts should be made to unify vaccination procedures and use the same vaccine for each dose.

　　Vaccination with nine-valent vaccine will not cause diseases caused by HPV?

　　No vaccine can achieve 100% protection.

　　All HPV vaccines can provide a high level of protection against types 16 and 18 (about 70%). HPV vaccine also provides some cross protection for some types that are not included in the vaccine.

　　Nine-valent HPV vaccine will increase the proportion of preventing cervical cancer from 70% to 90%. However, because it fails to cover all high-risk HPV types, nine-valent HPV vaccine cannot prevent all HPV-caused infections or diseases 100%. Cervical cancer screening after vaccination should be carried out as usual.

　　Who is not suitable for nine-valent HPV vaccine?

　　Severe allergic reaction to any active ingredient or adjuvant in HPV vaccine is contraindication. Those who have symptoms of hypersensitivity after vaccination should not be vaccinated again. (End)