HPV vaccination: Practice Facts

OBG-Speculum:    2024                       ISSN no.

Vol -2, Issue -1  

Dr Reena Srivastava, Dr Preeti Bala Singh

Cervical cancer is an important public/ health problem & majorly caused by high-risk strains of Human Papilloma Virus (HPV). 8 out of 10 women globally will get infected with HPV at some point in their lifetime. HR HPV type 16,18 ,31,33, 35, 39, 45, 51,52, 58, 59, 66 cause cervical cancer. Low risk type 6,11 cause anogenital warts. Persistent infection with high-risk HPV is a necessary cause cancer.

 Cervical cancer is the most common genital malignancy in Indian women with high mortality. Every 8 minutes a woman dies of cervical cancer in India. An estimated in 1 in 53 women in India will develop cervical cancer in their lifetime.       

Level I prevention -Prophylactic HPV VACCINATION can not only prevent cervical cancer but 4 additional cancers in women: vulvar, vaginal, anal and oropharyngeal & warts.

HPV vaccination timely i.e, before sexual activity and correct dose is the most successful tool for prevention of cancer cervix. 90% of girls to be fully vaccinated by age 15 yrs is the target proposed by WHO for 2030

Currently Bivalent (16,18), Quadrivalent (6,11,16,18) and Nona-valent (6,11,16,18, 31,33,45, 52, 58) vaccine is available

WHO now recommends:

·   A one or two-dose schedule for girls aged 9-14 years

·   A one or two-dose schedule for girls and women aged 15-20 years

·   Two doses with a 6-month interval for women older than 21 years

·   Catch up vaccination of older females upto 26 years is also recommended. Post-partum phase of 1st delivery at hospital can be utilized as a good time to inform, motivate and facilitate catch up vaccination. Catch-up vaccination requires 3 doses.

Women aged 27 to 45 years previously unvaccinated can be prescribed HPV vaccine after detailed information and shared decision that they may be already harbouring the HR-HPV strain and in that case vaccine will not be giving full protection.

·                Assault victim: HPV vaccination should ideally be part of sexual assault management. The 3 doses series is must whatever may be the age of victim with first dose at the time of initial examination.

·                HIV and immunocompromised cases like transplant recipients 3 dose schedule be prescribed even for girls of 9-14 years of age and Quadrivalent vaccine be preferred.

Indian Guidelines:

·       Girls through 9-14years: Two doses to be administered at an interval of 6 months, 0–6months.

·       Girls15 years and older: Three doses recommended in the schedule 0–1–6months for Bivalent Cervarix and 0–2–6months for Quadrivalent Gardasil & Cervavac (0-2-6month schedule). The second dose should be administered at least one month after the first dose and the third dose should be administered at least 3 months after the second dose. All three doses should be given within a 1-year period.

·       In immunocompromised individuals of any age: Three doses recommended in the schedule 0–1–6monthsfor Cervarix and 0–2–6 months for the Gardasil.

·       HPV-9 is licensed in a 3-dose schedule of 0-2-6 months in females 9-26 years of age.

·       The ideal age for starting the vaccine is 9-10 years.

·       HPV vaccines can be given at the same time as the Tdap vaccine.

·       There is no need of booster as per current evidence.

Here some important facts, useful for clinical prescription of HPV vaccine.

·                Most of the HPV infections are asymptomatic, therefore most people do not know when they are infected with HPV and even can transmit the HPV to their partners either way through sexual contact.

·                Vaccine prevents against the strains present in it and few more similar surface antigenic variants and not all HPV strains. If a vaccinated person is exposed to an HPV type not in the vaccine, they could potentially be infected and spread the virus to others.

·                The immune system takes one to two weeks to generate immunity. The 6th month dose is important because it enhances the immune response memory developed by 1st and 2nd dose. Maximum protection is there two weeks after receiving the 6month dose of any HPV vaccine. Immune response that develops before 15 years with two doses is equivalent to 3 doses after 15 years- (WHO / CDC). The interval of 6 month is critical to ensure adequate immune titers and durability of protection. If the interval is less than 5 months a third dose is required.

·                Record Uncertainity: If there is no record & uncertainty about the number of previously received doses of vaccine:   below 15 years -single additional dose and above 15 years should be advised 1 and 6-month dose. Extra doses are not likely to have negative effects.

·                Ideally the same vaccine should be given to complete the course, but if because of some reason, if previous received type of HPV vaccine is not known any type available (bivalent, quadrivalent, nanovalent) can be given. The 9-valent vaccine can be given in place of either of the previous Gardasil®-4 and Cervarix to complete a vaccination series,

·                Regular HPV vaccination results in lower rates of HPV infection among those who received vaccination, but also, to some degree, in those who have not been vaccinated. This phenomenon is commonly known as herd immunity.

·                Ideally vaccine schedule should been start prior to sexual exposure but sexually active girls and women can receive HPV vaccine with counselling, with the sense that she may not have been infected with all major oncogenic strains of HPV by now.

·                Woman above 20 years who are not in committed monogamous relationship, and women who recently or recurrently have STDs, should be counselled about the efficacy of vaccine.

·                Testing for HPV DNA prior to vaccination is not recommended at any age.

·                Interrupted vaccination schedule:

o        There is no need to start the vaccination again from the start. WHO has notified that single dose only below 15 years can give enough immune response. Vaccine series need not be restarted

·                The interval can be extended to even 12 to 18months if a dose is missed.

·                No definite maximum interval between doses have been recommended. Only one dose may even suffice (latest by WHO)

Pregnancy and HPV vaccination:

·                Routine pregnancy testing is not recommended before HPV vaccination.

·                If HPV vaccine received inadvertently during early pregnancy safety can be assured. There is no need for termination of pregnancy per say for this reason.

·                But HPV vaccination course should never be started in pregnancy.

·                If a vaccine series is started and patient become pregnant next doses to be withheld till post-partum period.

·                HPV vaccine can be given during lactational period to women 26 year and younger if not given in the past.

Safety & Efficacy

·                99% efficacy is there when given to women who have not been exposed to that particular HPV.  Efficacy grossly reduces if given above the age of 20years in sexually active cases. All the three available vaccines are being approved by FDA after successful trial over 15000 -30000 females.

·                The HPV vaccine contains aluminum like the hepatitis B and Tdap vaccines. Aluminum boosts the body’s immune response to the vaccine.

·                HPV vaccine helps in protecting future fertility linked to cervical/vaginal lesions and dose not harm.

·                Vaccine have been found safe in major post market surveys and now we have 8-10year data of it Apart from minimal side effects like pain, redness, at the injection site and malaise there is no definite complications.

·                Continued protection and persistent higher antibody levels have been observed after HPV vaccination compared to the natural infection-based immunity.

Women coming with abnormal Pap or Positive HPV test report

·                Women may be having one or more type of HPV infections. Not necessarily with the HR-HPV types responsible for cancer or included in the vaccine. Vaccine may Still provide protection against other HR-HPV types not already acquired by now. Proper counseling is must that vaccine will not have protective effect against pre-existing HPV infection / disease. Potential benefit will not be the same as in those vaccinated before sexual debut

·                HPV vaccine be Co-administered with other vaccines as COVID-19  DPT, Meningococcal conjugate vaccines. Each injection at different sites.

·                Vaccinated girls and women has to follow the screening protocol in the same manner as non-vaccinated ones. Cytology once in 3 years or Co-test once in 5 years.

Single dose vaccine: The world health organization’s [WHO] strategic advisory group of experts (SAGE) on immunization concluded that a single dose of human papillomavirus (HPV) vaccine delivers solid protection against HPV. A single-dose HPV vaccination schedule could alleviate financial and logistical barriers,

Join hands to stop cervical cancer before it starts

Reference:

1.               WHO update recommendations on HPV schedule: https://www.who.int/news/item/20-12-2022-WHO-updates-recommendations-on-HPV-vaccination-schedule

2.               Talking to parents about HPV vaccine. https://www.cdc.gov/hpv/hcp/for-hcp-tipsheet-hpv.pdf

3.               HPV vaccine recommendations. https://www.cdc.gov/vaccines/vpd/hpv/hcp/recommendations