Nzelu: Preventing cancer: The role of vaccines
THE 2015 theme for World Cancer Day (February 4) is ‘Not Beyond Us,’ which takes a proactive approach to the fight against cancer, highlighting that the solutions are available and accessible.
According to the World Health Organisation (WHO), one-third of cancer is preventable, another one-third is curable and the last third can have good quality of life with appropriate care. Vaccination is one of the most equitable low-cost, high-impact public health measures, when programmes are implemented on the national level. Eradicating the main viruses associated with cancer worldwide by implementing widespread immunization programmes could lead to a 100% reduction in viral-related cancers in 20 to 40 years, said Graham Colditz, of the Washington University School of Medicine, Missouri at the Union for International Cancer Control (UICC) World Cancer Congress 2012.
Hepatitis B (HBV) is major risk factor of liver cancer, which kills 11,663 Nigerians every year. Fortunately, HBV vaccine is now part of Nigeria’s National Immunization Programme (NPI), with the first dose being given at birth.
Human Papilloma Virus (HPV) is the root cause of more than 5% of cancers, including nearly all cervical cancers and a substantial percentage of cancers at other sites such as vagina, vulva (the outer part of the female genital organs), penis, scrotum, perineum, anus, head/neck, mouth, throat, nose, tonsil, skin, nail-bed, and conjunctiva (eye). HPV is the most common sexually transmitted infection (STI) in the world, with the highest prevalence in sub-Saharan Africa; 26% of women in Nigeria are positive for the virus. Almost all sexually active people get HPV at some point in their life. Although most HPV infections resolve spontaneously, about 10% persist and may progress to cancer.
There are three types of HPV vaccines – a bivalent vaccine (Cervarix), a quadrivalent vaccine (Gardasil) and a 9-valent vaccine (Gardasil 9). The bivalent vaccine protects against only 2 types of HPV (16 and 18) and is recommended for females alone for prevention of cervical cancer. The quadrivalent vaccine protects against 4 types of HPV (6, 11, 16 and 18). Gardasil 9 protects against the same 4 types of HPV as the quadrivalent vaccine, plus 5 other high risk types: 31, 33, 45, 52 and 58. The Gardasils thus prevent most cases of cervical cancer, and other cancers caused by HPV infection, including a proportion of genital, anal, oral and throat cancers. The Gardasils also prevent genital warts and Recurrent Respiratory Papillomatosis (RRP). The Gardasils are approved for both males and females. Vaccinating boys against HPV might also help protect girls from the virus by decreasing transmission.
Recurrent Respiratory Papillomatosis (RRP), most often linked with HPV types 6 and 11, occurs when warts grow in the breathing tubes and lungs. This is usually due to transmission of HPV from a pregnant woman with genital HPV to her baby during birth. RRP causes deadly asthma-like symptoms in children. It may rarely progress to cancer of the voice box. As mentioned earlier, Gardasil helps to prevent RRP.
HPV vaccine is given in three doses over six months. The protection from the vaccines is expected to be life-long. The vaccines are best given before the start of sexual activity and therefore, exposure to HPV. The recommended age-range for routine immunization against HPV is 9 years to 26 years. However, studies have shown that Gardasil also protects women between 27 years and 45 years.
The HPV vaccines have been taken by millions of people worldwide and have been found to be safe. The US Centre for Disease Control (CDC) recommends that people should get the same vaccine brand for all three doses i.e. Cervarix and Gardasil should not be used interchangeably. Because of the significant advantage of the quadrivalent vaccine over the bivalent vaccine, the former (i.e. the quadrivalent vaccine or Gardasil) is currently given free to teenagers, under the NPI of several developed countries including Australia, the UK, Singapore and New Zealand.
Unfortunately, the cost of the vaccine is prohibitive and out of the reach of the poor in developing nation. HPV vaccines cost about US$130 per dose in developed nations, excluding the cost of giving the injections. Fortunately, in 2013, the vaccine manufacturers offered the Global Alliance on Vaccines and Immunisation (GAVI) a reduced price of US$4.50 per dose. This reduction was made in order to ensure access for developing countries, who need the vaccine most. All countries with Gross national income (GNI) per capita data equal or below US$ 1,580 are eligible to apply for support from GAVI. However, for GAVI new vaccines support, only countries with three doses of diphtheria, tetanus and pertussis vaccines (DTP3) coverage levels greater than or equal to 70%, may apply.
Nevertheless, countries which have not attained DTP3 coverage levels of up to 70% may apply to GAVI for HPV demo. The HPV demo means that poor countries that have not yet established the ability to deliver HPV vaccine could be supported by GAVI to implement a two-year demonstration programme.
Nigeria, with DTP3 coverage of 41% does not qualify for full GAVI support. However, Nigeria is eligible for the HPV Demo programme. How are we taking advantage of this golden opportunity to include HPV vaccine into our NPI? Uganda, Tanzania, Kenya, Ghana and many other developing nations are trailing the blaze. For instance, Uganda achieved 89% coverage for Gardasil prior to its incorporation into their NPI. Our children deserve as much!
We must note that in spite of the importance of HPV vaccine in preventing cervical cancer, women who have been vaccinated still need to have regular cervical screening. This is because none of the vaccines currently available can protect against all the 14 types of HPV known to cause cancer. Other protective measures include sexual discipline, non-smoking and optimal female hygiene (details on blog page of www.cecpng.org).
Cervical screening is a way of picking up abnormal cells in the cervix before they progress to cancer. According to UK National Health Service (NHS), even without vaccination, early detection and treatment of cervical abnormalities detected by screening can prevent three-quarters of cervical cancers. Vaccines do not treat HPV infection and should not be used as treatment of abnormal cervical changes. Given the fact that cervical cancer is the easiest of all cancers to prevent, it is sad to note that it remains the leading cause of cancer deaths in African women. Cervical cancer kills a Nigerian woman every hour. The rural woman is worse off, because of the near total absence of facilities for screening and treatment.
To combat this cancer menace, the mass medical mission pioneered community-based mass cervical cancer screening campaign in Nigeria, known as the National Cervical Cancer Prevention Programme (NCCPP). This initiative was renamed the National Cancer Prevention Programme (NCPP), following the inclusion of other cancers. In spite of its limited resources, since its establishment in 2007, over 100,000 Nigerians have been directly screened and treated and through the awareness created, the NCPP has helped to protect millions of Nigerians from cancer. Furthermore, the NCPP has been in the forefront of advocacy for universal and free availability of HPV vaccine. In fact, the launch of Gardasil in Nigeria took place at the NCPP centre in 2009 by the late Prof. Dora Akunyili.
The monumental effort of NCPP has significantly contributed to a 15% reduction of cervical cancer deaths in Nigeria, from 26 women dying daily to 22 daily, between 2008 and 2012 (WHO data). The improvement is proof positive that if we could scale up the present effort, then victory in the Big War against Cancer, is not beyond us!
The current focus of the Committee Encouraging Corporate Philanthropy (CECP-Nigeria) is to acquire and deploy Mobile Cancer Centres (MCC), which will energize the impact of NCPP. The MCC is a veritable tool that could potentially improve the immunization coverage of Nigeria, thereby facilitating the full support of GAVI in providing nationwide free HPV vaccination for Nigerians.
The CECP hereby invites all public-spirited people to participate in the upcoming National Cancer Week (June 7- 14, 2015), which is dedicated to fund-raising for the acquisition of the MCC. (Please see www.cecpng.org, for details).
Meanwhile, to mark the International Women’s Day, there shall be FREE BREAST and CERVICAL CANCER SCREENING on Saturday, March 7, 2015, at the Presbyterian Church, Yaba, Lagos. All females aged 18 years and above are welcome.
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