ReviewIntroducing human papillomavirus vaccines into the health system in South Africa
Highlights
► South Africa has a high incidence of cervical cancer. ► Two prophylactic HPV vaccines are registered in South Africa. ► Target group for HPV vaccine are adolescent girls, before start of sexual activity. ► The HPV vaccine could be delivered through EPI programme or through school system.
Introduction
South Africa is classified as an upper middle-income country by the World Bank [1]. The Gross Domestic Product is around $5800 per capita but the distribution is unequal. The rate of poverty (the percentage of the population living below the national poverty line as defined by the World Bank) declined significantly over the last few years but still stands at 23%. South Africa spends 3% of its GDP and just over 15% of government expenditure on healthcare. When compared to low- and middle-income countries the level of total health expenditure is relatively high. This high spending does unfortunately not translate into a healthy population [2]. Human development challenges are enormous and there is a low life-expectancy of only 51 years.
Accurate data on causes of death are not always available and cancer statistics are often lacking and inaccurate [3]. Cancer prevention as a health priority has to compete with communicable diseases like HIV and tuberculosis. Partly related to the poor quality of cancer preventative services there is a high incidence of cervical cancer in South Africa.
South Africa has a two tier medical system with considerable overlap. Approximately 20–25% of the population is covered by private medical insurance and makes use of modern, generally well-resourced, private sector facilities. Approximately 75–80% of the population depends on the state sponsored health-care of which the quality is quite variable according to geographical areas. A small but significant part of the population will access primary care in the private sector but will use the public sector for hospitalisation and specialised services.
Section snippets
The burden of HPV associated disease
Persistent HPV infection with an oncogenic strain of HPV is a necessary risk factor for the development of invasive cervical cancer [4]. The most important oncogenic viruses seem to be similar in many different geographical areas and HPV16, 18 and 33 were identified in the majority of cervical cancer biopsies from South Africa [5]. Oncogenic strains of HPV have the ability to integrate viral DNA into the human genome. The onco-proteins E6 and E7 deactivate important processes associated with
Cytology
The South African National policy for cervical cancer prevention was launched in 2000. The screening programme offers three Papanicolaou smears per lifetime starting after the age of 30 at 10-year intervals [17]. This policy is based on a mathematical model that predicts a reduction in cervical cancer incidence in excess of 60% if the policy is universally introduced. If a low-grade abnormality is found the cytology smear is repeated after 12 months. Referral threshold for colposcopy include
The role of Human Immune Deficiency Virus (HIV) co-infection
Southern Africa has the highest incidence of HIV-infected individuals anywhere. Despite that the biggest anti-retroviral programme in the world has been rolled out over the last few years, the life expectancy of South Africans has fallen drastically largely due to an excess mortality associated with AIDS related illnesses. One of the recognised HIV associated diseases is cervical cancer and its precursors. Unpublished data collected at the first author's institution confirms the fact that HIV
Treatment facilities available in Southern Africa
Treatment facilities for invasive cervical cancer are limited. Despite the fact that most cancers are diagnosed quite late, a significant number of women qualify for radical surgery as primary treatment. There are less than 20 registered gynaecological oncologists in the country. Radiotherapy facilities are in high demand and waiting lists for treatment are often unacceptably long. Palliative support is lacking in many parts of the country particularly in rural areas.
Primary preventative strategies
HPV vaccines are produced using recombinant technology, whereby the L1 capsid protein is inserted into a host (e.g. yeast or baculovirus). These L1 proteins can self-assemble into empty shells or virus like particles (VLPs) that are similar in size and shape to the HPV virion. VLPs do not contain viral DNA, and are therefore non-infectious and non-oncogenic [30], [31].
Currently there are two vaccines registered in South Africa: the bivalent vaccine Cervarix™, containing VLP antigens for HPV
Public health
The vaccines are recommended for prophylactic use, they do not clear an existing infection or disease. In order for the vaccine to be effective in preventing HPV infection, it must be given before exposure to HPV, which is before sexual debut. Studies on the natural history of HPV infection and disease have shown that the peak incidence of HPV infection occurs in most populations within 5–10 years of first sexual experience (age 15–25 years). There may be some differences between countries but
Introduction of a population based vaccination programme
Internationally HPV vaccines are not marketed as low cost items. In a health economics equation the cost of immunisation must be weighed against the cost of screening and treatment for cervical cancer with the understanding that the cost saving benefits of immunisation will only become apparent in one to two decades. The principle of justice dictates that medical care should be available to all who need it including economically disadvantaged communities.
A recent calculation of cost
Programmatic issues for South Africa
Vaccination of older children/young adolescents is not common in developing countries. Pilot studies are necessary in advance of a national immunisation programme. The studies should serve as evidence for the South African government on how to introduce HPV vaccination into the preventive armaments of health programmes.
Schools serve as trusted sources for education and could be used for conveying carefully crafted health messages about HPV and vaccination. School based immunisation programmes
Conclusions
During the past 20 years tremendous insight into the oncogenic process leading to invasive cervical carcinoma has been gained. Major progress has also been made in the understanding of the oncogenic potential of the HPV virus. At the end of 2002 the first HPV16 VLP vaccine trial was published where prevention of infection was proved [71]. In a population where childhood immunisation is already a way of life, even in rural South Africa, HPV vaccination may be the best solution for a very serious
Conflict of interest statement
None declared.
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