Categories
Uncategorized

Human papillomavirus (HPV) vaccine

HPV vaccines work by preventing new infections, and they do not prevent progression of HPV infection to disease.

HPV vaccination, likely prevents HPV infections, pre-cancers and cancers.

Vaccines do not improve clearance of HPV infection, or treat HPV related disease.

Quadruple HPV vaccine for types 6,11,16, and 18 rate for females aged 13-26 years who have not been previously vaccinated previously.

HPV vaccine now covers 9 types of HPV and approved for all individuals starting at nine years of age and extending up to 45 years of age, and is most effective before sexual debut.(HPV 16, 18, 31, 33, 45, 52, and 58.

The HPV types presented by the nine valent vaccination accounts for approximately 90% of HPV arrtibutable cancers worldwide.

Reduces the risk of HPV infection, cervical cancer and other HPV related disease among women 25 to 45 years who have not been infected with HPV strains targeted by the vaccine.

Administered intramuscularly on a 3 dose schedule, with 2nd and 3rd doses given 2 and 6 months after the initial dose, respectively.

The three doses  have been reduced to two and is likely a single dose of the current vaccine will confer a long-term immunity.

Most studies show, maximum benefits from vaccination administered prior to age 14 years, with decreasing effectiveness with age.

Can be administered concurrently with tetanus, diptheria and pertussis and meningococcal conjugate.

Contraindicated in pregnant women but not lactating ones.

May be less effective in immunocompromised women.

Most efficacious when administered prior to virus exposure, and it can be given starting at age 9 years: two doses of HPV vaccine are given 6 to 12 months apart prior to the 13th birthday.

Cervical screening is still recommended in vaccinated individuals.

The quadrivalent is HPV vaccine is presently approved for the prevention of genital warts in young men and is recommended for use in boys and young men 9-26 years of age.

In a randomized, placebo-controlled, double-blind trial of 4065 healthy boys and men aged 16-26 years of age the use of quadrivalent HPV vaccine against types 6, 11, 16 and 18 prevented infections of external genital lesions (Giuliano AR et al).

In the above study the efficacy of the vaccinated group was 60.2% for all HPV infections and 65.5% for lesions related to HPV 6, 11, 16 or 18, and in the per-protocol population efficacy was 90.4% (in this group patients received all three vaccinations and were negative for HPV at enrollment) (Giuliano AR et al).

The quadrivalent is HPV vaccine is it effective in preventing anal intraepithelial neoplasia, a precursor to anal cancer, in men (Palefsky, J).

In younger aged females the use of HPV vaccine results in higher titers of antibody than in women aged 16-26 suggesting the importance of vaccination at an early age (Villa L).

Most common adverse reaction to HPV vaccine is local pain, swelling and redness at the injection site.

Vaccine associated with less than 1% serious adverse effects, similar to placebo.

HPV vaccines are highly effective and well tolerated.

Studies show HPV vaccines have a long lasting protection after vaccination,  for many years.

There is no minimum protective antibody titer that has been identified.

Studies show high levels of immunogenicity for patients at age 45 years.

In females the use of the quadrivalent vaccine is associated with an increased likelihood of syncope on the day of administration, and they should be observed for 15 minutes after the administration of the HPV vaccine.

Guillain-Barre syndrome has been reported in a number of cases folowing its administration but the number still falls within the expected natural occurrences of 1-2 per 100,000 person-years in non vaccinated individuals.

A bivalent HPV vaccine (Cervarix), is available and provides coverage against HPV genotypes 16 and 18 that are associated with the vast majority of cervical cancers and cervical intraepithelial neoplasia.

The quadrivalent and bivalent vaccines are approximately 93-90% effective in reducing high grade CIN occurrence caused by HPV genotypes 16 or 18 within 3 years of vaccination.

Both vaccines are highly immunogenic in boys and men, and can be demonstrated to be 90% effective in reducing external genital lesions induced by HPV genotypes 6, 11, 16, and 18.

The quadrivalent vaccine is now recommended for routine use for 4 boys and young men 9-26 years of age to prevent genital warts and other HPV related disease.

Also protects against HPV types 6 and 11 which cause about 90% of condylomas, ref2241ed to as genital warts.

Maximum reduction in condyloma risk is seen after three doses of Quadrivalent HPV vaccine, and two doses of the vaccine is also associated with a considerable reduction in condyloma risk.

The 9-Valent HPV vaccine prevented disease related to HPV 31, 33, 45, 52, and 58 in a susceptible population (Joura EA et al).

The 9-valent HPV vaccine (Gardasil 9 [9vHPV]) is the only available vaccine in the United States shown to decrease the risk of certain cancers and precancerous lesions in males and females aged 9-45 years. 

 

9vHPV vaccine covers HPV subtypes 6, 11, 16, 18, 31, 33, 45, 52, and 58. 

Children and adolescents aged 15 years and younger need two, not three, doses of the 9vHPV vaccine; this ACIP recommendation stems from the vaccine’s enhanced immunogenicity in preteens and adolescents aged 9-14 years. 

The 9-Valent HPV vaccine generates an antibody response to HPV-6, 11, 16, and 18 that is noninferior to that generated by the qHPV vaccine.

HPV vaccine is not associated with an increase in sexually-transmitted disease and that vaccination is unlikely to promote unsafe sexual activity (JENA AB et al).

International randomized controlled trials involving female adolescents and women, 15 to 26 years of age of shown vaccine efficacy of at at least 96% for the prevention of surgical pre-cancers owing to vaccine targeted HPV types in women who had no evidence of infection, or exposure to a given HPV type at the time of vaccination and received all three vaccine doses.

Trials of the quadrivalent vaccine showed 100% efficacy for the prevention of anogenital warts.

HPV type specific antibodies develop in almost all of the vaccine recipients, and titers are substantially higher than after natural infection.

The effectiveness of prophylactic HPV vaccination is less well defined for oropharyngeal cancer than for anogenital and cervical cancers.

An Indian study found a single dose of HPV vaccine provided similar protection against persistent infection from HPV 16 and 18, the genotypes responsible for nearly 70% of cervical cancers, to that provided by two or three doses (Basu P).

HPV vaccination in the United States has led to herd protection against oral HPV 16, 18, 6, and 11 infections in unvaccinated men, suggesting  prevention of oral HPV infections and related oral pharyngeal cancers.

Since HPV can linger and infect the cells of organs other than the cervix, including the anus, penis, and throat, and can cause a range of cancers as well as genital warts the HPV vaccine recommendations should be followed.

In men, a trial of the quadrivalent HPV vaccine had an efficacy for the prevention of HPV type related lesions of 90.4%.

Studies of two dose or even one dose vaccination have revealed high efficacy rates.

Safety concerns, death, autoimmune conditions and ‘neurologic conditions have not occurred.

Over a lifetime, cervical cancer develops in up to 5% of an unscreened population, and effective screening and treatment of cervical pre-cancers can reduce the lifetime risk to less than 0.5%.

Leave a Reply

Your email address will not be published. Required fields are marked *