HPV vaccine

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  • human papilloma virus (HPV) virus-like particles (VLP) can be produced via the synthesis and self-assembly of the major virus capsid protein
    • these HPV L1 VLPs exhibit morphological and antigenic properties that are virtually identical to native virons - these properties have been utilized in the development of HPV L1 VLP subunit vaccines
    • at present, data reveals that all women receiving the HPV vaccine have seroconverted - because of this there are no immune correlates which denote protection
      • note though that the anti-VLP antibody responses in VLP-immunized women are markedly greater than that identified in natural infections

In the UK:

HPV vaccine recommendations

From September 1st 2019, the HPV vaccine recommendations will be as follows:

  • all adolescents in school year 8, (usually aged 12-13 years)
  • MSM (men who have sex with men) up to and including 45 years of age, attending participating sexual health or HIV clinics, regardless of risk, sexual behaviour or disease status

Boys aged 13 to 25 years

  • boys in the eligible cohort (born after 01/09/2006) remain eligible to receive the vaccine until their 25th birthday

Recommended vaccine

  • Gardasil is the currently recommended vaccine for the universal HPV vaccination programme. It is the only market-authorized quadrivalent HPV vaccine in the UK, it is approved for use in males and females from 9 years of age and it is the vaccine that has been used in the existing girls programme since 2012

  • Gardasil provides protection against four HPV strains: HPV16 and HPV18, two high risk HPV types that can lead to cancer; and HPV6 and HPV11, the two HPV types that cause approximately 90% of all anogenital warts in males and females
    • the vaccine supplied for the programme will change from Gardasil (R) to Gardasil (R) 9 during the 2021 to 2022 academic year

  • vaccine is made from the proteins that make up the outer coat of the virus types. These proteins assemble into small spheres that are called virus-like particles (VLPs). VLPs are not infectious and cannot cause HPV-associated cancers or genital warts as they do not contain the virus's DNA. However, VLPs are very immunogenic, which means that they induce high levels of antibody production by the body. Following vaccination with HPV vaccine, the immune system should mount a response against the VLPs. Upon subsequent expsosure to to the live virus, the immune system reacts quickly to prevent infection

From 1 April 2022, those individuals who would have been eligible to receive 3 doses (ie eligible MSM, and those aged from 15 to 25 years of age who remain eligible under the NHS universal adolescent programme), will only require 2 doses, at least 6 months apart, to be fully vaccinated. Individuals who start the NHS HPV vaccination programme prior to April 2022 should continue on the planned 3 dose schedule (7)

  • those who commence prior to April 2022 whose schedule is interrupted/delayed such that they had an interval of 6 months or more between their first and second dose only need a 2 dose schedule (do not require a third dose)

A 3 dose schedule should still be offered to individuals who are known to be HIV-infected,including those on antiretroviral therapy, or are known to be mmunocompromised at the time of vaccination (7)

Notes:

  • HPV is a double-stranded DNA virus that infects the surface of the skin and mucosae of the upper respiratory and anogenital tracts
    • are over 100 types of HPV viruses of which about 40 infect the genital tract
      • classified as being either high risk or low risk depending upon their association with the development of cancer
        • Types 16 and 18 are high risk and types 6 and 11 are low risk
        • Types 16 and 18 account for around 80% of all cervical cancers, the remaining 20% are due to 11 other high-risk HPV types
          • the proportion of cancers of the anus, penis, mouth and throat, vagina and vulva which are related to a high-risk HPV infection (and which are caused by types 16 and 18) vary by cancer site
        • majority of HPV infections do not cause any symptoms and infection is usually cleared by the body's own immune system without the need for other treatment
          • 70% of new high risk infections will clear within a year
          • 90% of new infections clear within 2 years
        • persistent infection with high risk HPV types such as types 16 and 18 can cause cell changes leading to lesions, warts or ano-genital cancers. These include cancer of the cervix, vulva or vagina in women, cancer of the penis in men and some cancers of the head, neck, throat or anus in either sex. Other types of HPV such as 6 and 11 cause genital warts which is the most commonly-diagnosed viral sexually-transmitted infection in the UK
    • Transmission of HPV
      • HPV infections are spread primarily by sexual contact with an infected partner, particularly through sexual intercourse but also by non-penetrative genital contact, including oral sex
      • HPV is one of the most commonly transmitted sexually-transmitted infections in the UK and anyone who is sexually active can contract it. The risk of acquiring infection increases with the number of previous sexual partners, the introduction of a new sexual partner, and the sexual history of partners
      • Infection commonly occurs soon after sexual debut and almost 40% of women are infected within two years (5)

Reference:

Last edited 02/2022

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