The Zhejiang Provincial Center for Disease Control and Prevention announced on March 15th that there have been new adjustments to the HPV vaccine immunization program.
The main change in this adjustment is for women aged 9-14 years old. The bivalent and nine valent vaccines have been updated from the original 3-dose immunization program to have the option to choose between 2 or 3 doses. If two doses of vaccination are selected, that is, one dose in 0 and one dose in June, with an interval of no less than 5 months.
It should be emphasized that among women aged 15-45, only three doses of the immunization program can be chosen. In addition, among the HPV vaccines currently available on the market, the quadrivalent vaccine requires 3 doses to complete the entire immunization process.
In addition to the Zhejiang Provincial Center for Disease Control and Prevention, several city centers for disease control and prevention in cities such as Dalian and Harbin have recently updated their vaccination plans for HPV vaccines, allowing young women (9-14 years old) to choose between two doses of bivalent and nine valent HPV vaccines.
In fact, although the current vaccination schedule for bivalent and nine valent vaccines is still 3 doses, it is a common consensus among industry experts to administer 2 doses of HPV vaccine to girls aged 9-14. Zou Shien, the chief physician of the Obstetrics and Gynecology Hospital affiliated with Fudan University, told a reporter from First Financial last year, "According to the current HPV vaccine immunization program, three doses are administered, and teenagers aged 9-14 can receive two doses."
However, there have been increasing clinical data indicating that the first dose of HPV vaccine can still provide immune protection three years after vaccination. So, for women aged 15-45, can we postpone the vaccination time for the second and third doses and wait for immune protection to weaken before getting the second and third doses?
In response, an HPV vaccine researcher told a reporter from First Financial News, "Currently, the recognized clinical results and instructions recommend a three shot immunization program, requiring the three shots to be administered within six months, with intervals of three months. Personally, I believe it is necessary to receive a second dose of booster, which can be administered within six months after the first dose. Whether or not to receive the third dose can be chosen by the individual."
In recent years, the World Health Organization has begun advocating for reducing the number of doses of HPV vaccines, recommending that countries provide one or two doses of the vaccine for women aged 9 to 20. Recently, MSD also announced the launch of clinical trials for single dose administration of the nine valent HPV vaccine to evaluate the efficacy and safety of single dose HPV vaccine in males and females aged 16 to 26.
HPV is one of the common viruses that infect humans and is also a significant cause of cervical cancer. There are over 200 subtypes of HPV, but not all subtypes can cause cervical cancer. In clinical practice, HPV can be classified into high-risk and low-risk types based on their carcinogenicity. Persistent infection of high-risk HPV is a high-risk factor for the development of cervical cancer. Among high-risk HPV types, cervical cancer caused by types 16 and 18 accounts for 70% of HPV infection related cervical cancer.
Data shows that women who engage in normal sexual activity have an 80% chance of contracting at least one type of HPV in their lifetime, but most are asymptomatic transient infections that can be cleared by their own immune system within 6-18 months.
There are currently bivalent, tetravalent, and nine valent HPV vaccines available on the market. The bivalent HPV vaccine can prevent HPV infection of types 16 and 18; The quadrivalent HPV vaccine can prevent HPV infections of types 6, 11, 16, and 18; The prevention coverage of the nine valent HPV vaccine is wider, and it can prevent HPV infections of types 6, 11, 16, 18, 31, 33, 45, 52, and 58. Among the various HPV vaccines that have been launched, except for a few bivalent vaccines that are suitable for women aged 9-30, the rest can be suitable for women aged 9-45.
Research has shown that bivalent and tetravalent vaccines have a protection rate of up to 98% to 100% against high cervical, vaginal, and vulvar lesions caused by HPV16/18; The nine valent vaccine can also prevent about 97% of highly pathological changes in the cervix, vagina, and external genitalia caused by HPV31/33/45/52/58.