Medical Guidance/Deng Minduan, Chief Physician of Gynecology and Obstetrics and Deputy Director of Gynecology and Pediatrics, Guangzhou Red Cross Hospital
In recent days, mainland women’s attention to HPV vaccine has been exploded again: first, the bivalent HPV vaccine was approved by the State Food and Drug Administration, and the vaccination age was relaxed from 9 to 25 years old to 9 to 45 years old; The next day, the nine-valent HPV vaccine, which was just approved in the mainland at the end of April, was listed in Boao, Hainan, and the listing of other provinces and cities in the mainland was just around the corner.
As a result, there are three different "price" HPV vaccines in the Mainland for women to choose and vaccinate. With more choices, there will be more natural entanglements: "At the age of bivalent and tetravalent, which one is better?" "I’ve been vaccinated with bivalent or tetravalent before, and now nine valence has come out. Is it necessary to go to ‘ Fill a needle ’ " ? Deng Minduan, chief physician of obstetrics and gynecology and deputy director of gynecology and pediatrics of Guangzhou Red Cross Hospital, analyzed all aspects of HPV vaccine for everyone.
Text/Guangzhou Daily All-Media Reporter Wu Wei Correspondent Hu Yingying
Bivalent and tetravalent can prevent 70% of cervical cancer, and nine valence can prevent 90%.
Deng Minduan introduced that there are currently three kinds of HPV vaccines listed at home and abroad, namely bivalent, tetravalent and nonavalent vaccines. In the second half of last year and the beginning of this year, the second price and the fourth price were listed one after another in the mainland of China, and the ninth price is about to be fully listed. Valence represents the number of HPV subtypes prevented: the more valences, the more HPV subtypes prevented, and the higher the preventive efficacy. The above three vaccines can prevent HPV16 and 18 subtypes from infection. These two subtypes of virus infection are the most common causes of cervical cancer, accounting for about 70%, so the incidence of cervical cancer can be significantly reduced after vaccination.
Compared with the first two vaccines, the nine-valent vaccine is different in that cervical cancer can be reduced by 70% after vaccination with bivalent vaccine; After vaccination with tetravalent vaccine, it can not only reduce 70% of cervical cancer, but also prevent 90% of genital warts (a common sexually transmitted disease); After inoculation with the nine-valent vaccine, the incidence of cervical cancer can be further reduced (it can reduce cervical cancer by 90%) on the basis of the four-valent vaccine, and it can also prevent genital warts by 90%.
If you are vaccinating bivalent or tetravalent vaccine now, can you switch to nine-valent vaccine to continue vaccination? Deng Minduan said that it is not recommended to mix and play. Different vaccines have different preparation processes, so it is recommended to continue vaccination according to the original plan. Then, I have been vaccinated with three doses of bivalent or tetravalent vaccine before. Is it necessary to vaccinate with nine-valent vaccine now? "Under normal circumstances, there is no need to vaccinate Jiujia. Because bivalent or tetravalent vaccine has a good effect of preventing cervical cancer, it can reduce cervical cancer by 70%, and the nine-valent vaccine only reduces cervical cancer by 20% on this basis. From the perspective of health economics, it is not necessary to vaccinate the nine-valent vaccine again. Of course, if the individual’s economic ability can afford it, it is another matter and you can consider it yourself. "
Key population of HPV vaccination: women aged 9-14.
Women who continue to pay attention to HPV vaccine will find that the applicable population of HPV vaccine in mainland China is different from other places. Deng Minduan explained that this was mainly because the age of the observed subjects in the clinical research before the vaccine was marketed in mainland China was different from that in other regions and countries. Therefore, it cannot be said that it is ineffective to vaccinate people outside the age specified in the instructions. However, before the instructions are updated, at present, vaccination can only be carried out in accordance with mainland regulations.
In fact, regarding the optimal vaccination age of HPV vaccine, the World Health Organization once pointed out in its position statement on HPV vaccine in May 2017: "The primary target population of HPV vaccine is women aged 9-14 before having sex for the first time". Because HPV virus is mainly transmitted through sex, the older you are, the higher the possibility of having sex, and the protective effect will be weakened after being vaccinated with HPV virus. In addition, the immune response of young women after vaccination is stronger than that of the elderly, and more antibodies are produced. Therefore, the focus of vaccination is on women aged 9-14 before their first sexual intercourse.
However, due to the different regulations on the applicable population of vaccines in mainland China, women aged 9-14 can only be vaccinated with bivalent vaccines for the time being.
According to the position statement of WHO in 2017, the protective effect lasts for at least 8-10 years after vaccination with bivalent and tetravalent HPV vaccines; After inoculation with nine-valent vaccine, the protective effect lasted for more than 5.6 years. Because the vaccine has not been on the market for a long time (especially the nine-valent vaccine), the related research is still going on, and maybe there will be a clearer statement in the future.
There is no need to test HPV before vaccination.
Some women think that it is necessary to test whether there is HPV infection before vaccination. In this regard, Deng Minduan said that it is not necessary, because the more the price of the vaccine, the more virus subtypes are prevented. In general, very few people are infected with virus subtypes that are completely consistent with the vaccinated vaccine. Therefore, even if one or two subtypes are infected, vaccination can still obtain the protection of other subtypes.
In addition, HPV can be repeatedly infected. Some studies have found that even if infected with a subtype of virus, or even caused cervical lesions, vaccination after treatment can reduce the recurrence rate of the disease. Therefore, it is not necessary to carry out HPV testing before vaccination.
However, if this woman happens to be at the time of cervical screening, or has never been screened, she can be screened at the same time as vaccination.
Deng Minduan introduced that HPV vaccine can be vaccinated during menstrual period, and you can have sex after vaccination, but it is recommended to use contraception temporarily until you have finished 3 shots and completed the whole vaccination procedure. If unexpected pregnancy is found during vaccination, it is recommended to stop vaccination immediately, and the remaining vaccines should be vaccinated after delivery and lactation. "Regarding the safety of pregnancy during HPV vaccination, the research data in this field in the world is extremely limited. According to the existing research data, the risk of adverse pregnancy events such as fetal congenital abnormalities and spontaneous abortion has not increased, but it is best not to vaccinate indirectly during pregnancy. " He said.
Deng Minduan reminded that no matter which "price" vaccine is vaccinated, cervical cancer screening should still be carried out regularly after vaccination. Because the current vaccines can’t prevent cervical cancer 100%, even the nine-valent vaccine only reduces cervical cancer by 90%.
Men can also be vaccinated against HPV.
Deng Minduan said that cervical cancer caused by HPV infection is the second largest malignant tumor in young women, but HPV infection is not a "patent" for women, and men will also be infected.
Comparatively speaking, the burden of male malignant tumors caused by HPV infection is lighter, such as penile cancer, anal cancer, oropharyngeal cancer, etc., and the incidence rate is lower. Therefore, the effect of male HPV vaccination on preventing male malignant tumors is not very significant.
However, the study found that after a certain proportion of men vaccinated with HPV vaccine, it will also have an effect on reducing the incidence of cervical cancer in women. In addition, because the tetravalent and nonavalent vaccines can also prevent genital warts (a common sexually transmitted disease, which affects both men and women), and there are more than 32 million new genital warts worldwide every year, the World Health Organization recommends that men be vaccinated with tetravalent or nonavalent vaccines. The FDA also approved men aged 9-26 to be vaccinated with HPV.
However, at present, the three kinds of HPV vaccines (bivalent, tetravalent and nine-valent) approved by the mainland do not include men among the applicable population. Therefore, if men want to vaccinate tetravalent or nine-valent HPV vaccines, they can only go to the relevant countries or regions that have approved male vaccination.