Misinformation on safety, efficacy and benefits of the potent vaccine against the deadly Human Papilloma Virus (HPV) that causes cancer in men and women, and parental refusal to give consent, are impeding its uptake in the ongoing drive targeting school-age adolescents.
HPV is one of the most common sexually transmitted infections in the world and it can spread in monogamous relationships - even if someone waits until they get married to have sex, and only have it with one sexual partner, infection with the virus can still occur if the partner has been exposed - and when condoms are used. It is so common that nearly everyone will be infected at least once in their lifetime.
While most of these infections do not cause symptoms and will subside on their own, infection with certain high risk types of HPV (HPV-16 and HPV-18) can worsen and develop into cancer.
Kenya has a population of 16.2 million women aged 15-years and older who are at risk of developing cervical cancer and current estimates indicate that every year, 5,236 women are diagnosed with cervical cancer and 3,211 die from the disease.
In 2018, an estimated 570,000 women were diagnosed with cervical cancer worldwide and about 311,000 died from the disease. Effective primary (HPV vaccination) and secondary prevention approaches (screening for, and treating precancerous lesions) will prevent most cervical cancer cases.
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It takes between 10 and 20 years, or longer, from the time one is infected to develop overt cancer and the best time to vaccinate your daughter (and son) is between 9 and 12 years before they become sexually active - the risk of HPV infection is not only highest immediately after sexual debut, but biological response (antibody levels) following vaccination is greater in children aged 11 to 12 years compared to those older than 16 years.
It provides lifelong protection and girls and boys aged 13 to 26 and 13 to 21 years respectively should get the vaccine if they did not receive it earlier. While studies show that it’s safe and effective, as a precaution, adolescents should always be sitting, or lying down, during administration and be observed for 15 minutes to avoid serious injury related to a syncopal (fainting) episode.
The HPV vaccine prevents girls and boys from several cancers - cancer of the cervix, vagina and vulva in women; cancer of the penis in men; and cancers of the anus, mouth or throat in men and women - and the best time to give it is in preteenagers aged 11 or 12, or as early as 9-years before they become sexually active.
CDC estimates that in the US alone, with a total population of 300 million people, 79 million Americans are currently infected, in addition to 14 million new HPV infections occurring every year. Every year, there are about 26,000 HPV cancers in that country.
For best protection, one requires three shots over the course of six months, the second and third injections given one or two months, and 6 months after the first shot, respectively.
With some viruses, being infected once can protect against future exposure and reinfection. However, studies have shown that while most individuals infected with HPV are able to clear or control their infection, there is no evidence of lifelong protection from natural immunity after a first infection for two reasons.
First, compared to prophylactic HPV vaccination which provides lifelong protection, the antibody levels from natural infection are considerably lower than those observed in vaccination. Second, although infection with one type of HPV - there are over 100 subtypes - may provide some protection against that one particular type, it will not provide protection against other HPV types.
In Australia and Nordic countries with national HPV vaccination rates exceeding 80 per cent and targeting adolescent girls in schools, vaccinated women have remained cancer-free for 15-years with a significant reduction in early markers of HPV infection such as genital warts in young men and women, cervical precancerous lesions and cervical dysplasia.
HPV also causes cancer in men - penile cancer, anal cancer, and a subset of head and neck cancers, specifically, squamous cell carcinoma of the oropharynx at the base of tongue and the tonsils - and to achieve herd immunity, it’s important to vaccinate both boys and girls. Research from Australia has demonstrated that herd immunity does not occur when only young women are immunised. We have a method to prevent cervical cancer with screening, but we do not have screening for the cancers that HPV causes in males, so the only point of prevention that we can offer for males is vaccination.
In most low-income countries, access to centres that carry out screening and diagnosis is limited and awareness of the need for regular pap-smears is also low leading to many women presenting with advanced cervical carcinoma. Preventing these cancers through primary prevention with vaccination would be a real win for cancer prevention as a whole. Together, cervical cancer screening and the HPV vaccine could prevent as many as 93 per cent of all cervical cancers.
Routine screening should begin at age 21 years, even if the woman has had the HPV vaccine. Women aged 21-29 years should be screened with the Pap test every three years. Women aged 30-65 years have the option of either having a Pap test every three years, or having a Pap test plus an HPV test every five years. Screening more frequently than this does not provide more protection, and routine screening is not recommended after the age of 65 years, given a history of normal screenings.