Although not approved for marketing in mainland China, the HPV vaccine has become a hot topic of discussion nowadays. The HPV vaccination program is now available in Hong Kong and Macau, which is obviously good news for Guangdong as a neighbor to Hong Kong and Macau. As the most favorable weapon to prevent cervical cancer, the effectiveness of HPV vaccine has been confirmed in the past few years. With the total number of cervical cancer patients in China being the highest in the world, the HPV vaccine should be the most desirable gift for Chinese women from the perspective of disease prevention!
Many of our patients and friends are already interested in the HPV vaccine and asking questions about the vaccination. Although they have a lot of information in their hands, most of this “information” is obtained from “doujian”, which is inevitably mixed, and many of the “posts” even belong to the “watered down” products that will be harmful for years to come. The “watered down” products. To help more friends have a more comprehensive and correct understanding of HPV vaccine, I will summarize the relevant guidelines published by the American College of Obstetricians and Gynecologists (ACOG), the International Federation of Obstetrics and Gynecology (FIGO), the American Academy of Pediatrics (AAP) and the European Society of Gynecologic Oncology (ESGO) and publish them here.
1. The significance of HPV vaccination
HPV infection is a systemic disease. Cervical cancer, genital warts, vulvar cancer, penile cancer, laryngeal cancer, lung cancer, esophageal cancer and anal cancer are all related to HPV infection. Among these diseases, cervical cancer and genital warts in particular are closely related to HPV. 70% of cervical cancers are caused by type 16 or 18, while 90% of genital warts (such as condyloma acuminata) are caused by HPV type 6 or 11. The efficiency of vaccination against CIN II-III and vulvar warts caused by the corresponding HPV infection is close to 100%.
2. Who should receive the HPV vaccine?
The FDA and CDC recommend routine vaccination for both males and females between the ages of 11 and 12 years old, but this age can be adjusted according to state laws as early as 9 years old. If the vaccine is not administered at age 12, the catch-up age is 13-26 years. People aged 11-12 years who have not begun sexual activity will have the best immunization results after vaccination. A woman’s previous history of CIN, VIN or genital warts does not affect vaccination. The antibody response following vaccination is strongest in those vaccinated at age 9 and lasts up to 15 years.
In the United States, the FDA has not approved HPV vaccination for women older than 26 years of age, but vaccination is feasible for individual patients (off label), and these women still benefit slightly from vaccination. However, in Hong Kong, the upper age limit for the vaccinated population can be obtained at 45 years. It should be noted that HPV vaccination is gradually being promoted as a basic immunization program in the United States, with some states having complete coverage, while Hong Kong and Macau have not yet reached this level, and some vaccination is still a commercial activity, and differences in health economics policies between the two regions are possible reasons for the differences in age ranges of the vaccinated population. In addition, the older the age, the lower the concentration of antibody titers after HPV vaccination. Compared with the population aged 16-26 years, antibody titers after vaccination at the age of 9-15 years can reach twice the level of the former population, which is an important reason why vaccination is not strongly recommended for people aged 26 years or older.
HPV vaccination is not effective at age <9 years because the immune system is not fully established, and therefore HPV vaccination is not recommended for people aged <9 years.
Combining the opinions of existing guidelines and the current situation of obvious cervical cancer epidemiology in China, HPV vaccination is not recommended for people aged <9 years old, while other people can consider vaccination with their own needs.
3.What are the currently listed HPV vaccines? What are the types, effects, vaccination methods and contraindications?
There are only two vaccines approved by the FDA, Cervarix (Huoyancon, GlaxoSmithKline) and Gardasil (Gardasil, Merck). Both are inactivated vaccines with a capsid structure that does not contain viral DNA, and detailed information on both vaccines is available on the official website.
Both vaccines are currently available in Hong Kong and Macau: Cervarix is a bivalent vaccine, targeting HPV types 16 and 18; Gardasil is a quadrivalent vaccine, targeting HPV types 16, 18, 11 and 6. Both men and women can receive the quadrivalent vaccine, but the bivalent vaccine can only be used for women. Both vaccines are equally effective in preventing HPV 16 and 18 HPV infections associated with genital tract disease (CIN, cervical cancer), and the quadrivalent vaccine also prevents genital warts due to HPV types 11 and 6 infection.
Both vaccines are administered in a 3-dose regimen as follows.
Cervarix: dose 1 – any time (0 months); dose 2 – 1 month (1 month) after dose 1 injection; dose 3 – 6 months (6 months) after dose 1 injection.
Gardasil: dose 1 – any time (0 months); dose 2 – 2 months after dose 1 (February); dose 3 – 6 months after dose 1 (June).
Both vaccines are administered intramuscularly and immunization should be completed using the same vaccine as much as possible.
Contraindications: Women who have been determined to be pregnant before vaccination and those who are allergic to yeast should not be vaccinated.
4.Is the vaccination safe? What are the common adverse reactions?
The safety of the vaccine in the general population has been well established. As of the current location, more than 57,000,000 HPV vaccinations have been administered and no serious complications have been found to result from the use of the vaccine.
Common adverse reactions following vaccination include pain, muscle tension, local edema, masses, localized skin redness, headache, fever, nausea, dizziness, and vomiting. Some patients experience syncope during vaccination; therefore, consider lying down for vaccination and staying for 15 minutes after injection. If patients show adverse reactions consistent with hypersensitivity reactions after vaccination, subsequent vaccination needs to be cautious or terminated.
5. Will HPV vaccine affect the effects of other vaccines?
At present, no cross-reactivity has been found between HPV vaccine and other vaccines, so there is no conflict between simultaneous vaccination.
6.Does having sex before vaccination affect the effectiveness of the vaccine?
The HPV vaccination depends only on whether the vaccine belongs to the recommended population, therefore, the history of sexual life before vaccination does not affect the vaccination, but the preventive effect of the vaccine will be significantly weakened after vaccination for these people.
7. Is it possible to have sex during vaccination?
Reproductive tract contact is the main but not the only way of HPV infection. Therefore, sexual intercourse is possible during vaccination, but contraception is recommended.
8.Is it necessary to test for HPV infection before vaccination?
Testing for HPV before vaccination is not recommended for the following reasons.
① this practice will not bring any benefit to the patient.
②Even if one is infected with HPV, it does not affect the decision to get vaccinated.
③ Existing vaccines can prevent multiple HPV infections, and the likelihood of a woman being infected with multiple HPVs at the same time is extremely low.
9. Remedies for failure to follow the vaccination schedule
After any missed dose, there is no need to restart the vaccination, but simply continue to complete the follow-up vaccination.
10.Intensive program
The current three-dose vaccination program provides the most definitive and potent immunization effect. What is the longest duration of protection after vaccination? There is no clear answer to this question. However, based on the available evidence, it is not recommended to increase the number of injections or doses to enhance the immune response.
11. What should I do if I am pregnant, breastfeeding or pregnant during vaccination?
Both HPV vaccines are classified as Class B drugs in the FDA drug classification, and the HPV vaccine is an inactivated vaccine, which theoretically does not cause adverse effects on pregnancy. Although a medical record registry for vaccine use in pregnant women is in place, the safety of vaccination during pregnancy has not been fully evaluated. None of the four guidelines recommend testing women for pregnancy prior to vaccination, but contraception is still recommended during vaccination, and if pregnancy is detected subsequent vaccination should be discontinued until after delivery before continuing to complete the vaccination. HPV vaccination during breastfeeding is safe for both mother and child.
12. Can the HPV vaccine be effective in treating pre-existing lesions?
It is clear that the HPV vaccine has no therapeutic effect on existing lesions, such as CIN, cervical cancer, condyloma acuminata, etc.
13.Do I need to be screened for cervical cancer after HPV vaccination?
The HPV vaccine cannot target all types of HPV. At present, it is still recommended that all vaccinated women receive formal screening according to the existing screening protocol, which is the most important issue after vaccination.
14. The role of the obstetrician and gynecologist in HPV vaccination
According to the CDC, if immunization coverage with the HPV vaccine reaches 80% by age 12, the number of cervical cancer patients continues to decrease by 53,000 across the U.S. Obstetricians and gynecologists play a critical role in the vaccination program by having the opportunity to educate their female patients about the importance of having their children vaccinated against HPV at an age-appropriate level.