Human Papillomavirus Vaccination (HPV) Schedule

Introduction

HPV or human papillomavirus infections are one of the most common sexually transmitted diseases. There are about 200 different strains of HPV identified to date, with the potential to find more of them out there. HPV has been associated with many serious and fatal conditions like cervical cancer and head and neck squamous cell cancers. Although first discovered in 1900, it took more than 17 years to design, test, and conduct clinical trials on the HPV vaccine. The first commercially available, FDA-approved HPV vaccine was available in 2006, and by the second quarter of 2007, the vaccine was approved for use in over 80 nations. According to an October 2019 report, more than 100 countries now include the HPV vaccine in their regular immunization programs.

What Does the HPV Vaccine Cover?

There are three types of HPV vaccines commercially available in the market that are approved by the FDA for administration.

Three different FDA-approved HPV vaccines are available:

• 2vHPV (Bivalent Vaccine): Protection against HPV 16 and 18. Currently in use outside of the United States.

• 4vHPV (Quadrivalent Vaccine): Protection against HPV 6, 11, 16, and 18.

• 9vHPV (Nine-Valent Vaccine): Protection against HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58.

Gardasil-9, which is a 9-valent HPV vaccine, is the only HPV vaccine distributed in the United States. This vaccine provides protection against nine strains of the virus, namely HPV-6, 11, 16, 18, 31, 33, 45, 52, and 58.

Cervarix, which is a bivalent HPV vaccine, provides protection against the most common oncogenic genotypes of HPV- type 16 and 18 that are responsible for about 70 percent of cervical cancers. Gardasil shots prevent about 90 percent of genital warts. Gardasil-9 got FDA (Food and Drug Administration) approval in 2014, which expanded the coverage over the existing Gardasil vaccine (an increase of 5 stains) and covered another 20 percent of cervical cancer cases, bringing the overall cervical cancer protection to 90 percent. According to studies, HPV vaccination and at least twice screening for cervical cancer in a lifetime reduced cervical cancer incidences by 97 percent.

National vaccination programs cover just over 30 percent of the global target population, with some regions with very low coverage. The distribution is seemingly higher in developed countries than in developing nations, with about 32 percent of females between 10 and 20 years receiving complete HPV shots in developed countries. The highest coverage of HPV immunization is in countries like Australia, Denmark, and Sweden, where the coverage crosses 60 percent. On the other side of the spectrum, low-income nations reported less than one percent coverage of the target population. To counter this disparity, some underdeveloped countries like Bhutan and Rwanda have successfully introduced HPV in their national routine immunization schedule. There exists a great variance in penetration of coverage even within the countries like India, where 65.3 percent of the urban population got the shots, whereas less than two percent got them in rural zones. This is a great cause of concern as the rural population accounts for over 80 percent of cervical cancer deaths.

How Does the HPV Vaccine Work?

Vaccines, in general, contain dead and weakened viruses, or just the proteinaceous capsids. The intention of the shots is to evoke the body’s immune system to form antibodies against the purposefully introduced pathogens so that the same may be recruited in case of future actual infections. The current batch of approved vaccines contains virus-like particles or VLP as the HPV-containing segment of the capsid protein-L1. Due to the lack of any viral genome, the protein is considered non-infectious and non-oncotic. These VLPs can be safely produced using other microorganisms like bacteria, yeast, or even arthropod cells. Upon administration, the body’s humoral response gets activated. According to a study, the antibody title following complete vaccination was found to be 10 to 100 folds higher than what is produced following an actual infection.

Who Should Get Them?

HPV vaccinations are to be duly taken by both males and females between the ages of 9 and 45 to prevent the incidence of various conditions, including:

• Anal cancer.

• Oropharyngeal cancer.

• Cervical cancer.

• Vulvar cancer.

• Vaginal cancer.

• Head and neck cancers.

• Condyloma acuminata (genital warts).

• Cervical adenocarcinoma in situ.

• Anal, cervical, vulvar, and vaginal intraepithelial neoplasms.

Routine check-ups and HPV vaccination are recommended for certain at-risk populations that, include:

• Individuals between 9 and 45 years of age with no prior vaccination or incomplete regimen.

• Bisexuals and gays with an active sexual history.

• Immunocompromised patients with no or incomplete HPV vaccination history.

• Sexual abuse or assault victims.

• Transgenders.

What Is the HPV Vaccine Administration Regimen?

The HPV vaccine, specifically the 9vHPV vaccine, is administered as an intramuscular vaccine in the deltoid region (in the arm) or anterolateral thigh region. A single pediatric or adult dose contains 0.5 milliliters of the vaccine suspension and is administered as two or three dose schedules.

• Two-Dose Schedule (Ages 9 Through 14): The first dose is followed by the second dose within a year but with a gap of at least five months from the first. If the second dose is administered prematurely (within five months), then a third suspension shot is required four months after the second dose.

• Three-Dose Schedule (Ages 15 Through 45): First dose, followed by second dose after two months, and a final dose administered six months after the first.

According to CDC (Centre for Disease Control and Prevention) and ACIP (Advisory Committee on Immunization Practices):

• Routine HPV vaccination for all individuals at the age of 11 or 12.

• Vaccination is to be given to all individuals up to the age of 26 if not vaccinated earlier.

• Shared clinical decision-making for patients aged 27 to 45 years.

• Between 9 and 15 years: Two-dose schedules to be followed and a third dose in case of a premature second dose.

• Between 15 and 26 years: Three dose schedule for both healthy and immunocompromised individuals.

• Between 27 and 45 years: Shared-clinical decision-making as individuals getting vaccinated at this age do not get much protection. Unvaccinated or at-risk individuals might exact the most benefit from vaccination at this age.

• HPV vaccination is not to be administered to pregnant mothers but can be given to nursing mothers.

What Are the Side Effects of HPV Vaccination?

• Pain, redness, and swelling at the site of injection.

• Fever.

• Dizziness.

• Fainting.

• Headache.

• Tiredness.

• Nausea.

• Muscle pain.

• Joint pain.

• Anaphylactic reaction.

Conclusion

Human papillomavirus can cause a wide range of problems ranging from genital warts to various cancers. Vaccinations are one of the best ways to empower one's own body to fight any infectious changes. It must be of utmost importance for governments to strengthen the health sector and increase the penetration of immunizations. Since the bulk of cervical cancers is concentrated in rural areas and underdeveloped countries, they must be targeted at the earliest. Most of the cancers are either highly fatal or require too aggressive treatment to cure. Even then, there are chances of recurrence, and the pathway to remission is never easy. So it is advised to take up preventive measures like vaccinations when it is available, cutting the weed at its root, thus preventing having to suffer from future complications.