Age-specific prevalence of cervical human papillomavirus infection and cytological abnormalities in women in Gauteng Province

Abstract

Background. Women accessing the public health system in Gauteng province, South Africa are largely unscreened for cervical cancer and have a high background prevalence of human immunodeficiency virus (HIV) infection. Objectives. This cross-sectional study describes the age-specific prevalence of human papillomavirus (HPV) infection and cytological abnormalities among this urban and peri-urban population. Method. Over the period March 2009 -September 2011, 1 524 women attending public sector primary healthcare clinics were invited to participate in a cervical cancer screening study. All participants were screened with conventional cytology and HPV testing undertaken using the HPV linear array genotyping kit (Roche Molecular Systems). Results. Of 1 472 women with valid cytology results, abnormalities were detected in 17.3% (n=255), of which 9.1% (n=134) were high-grade squamous intraepithelial lesions, and 0.5% (n=8) suggestive of squamous carcinoma. Of the 1 445 women with complete data, the overall and high-risk HPV DNA prevalences were 74.6% (n=1 078) and 54.3% (n=784), respectively. HPV type 16 and/or 18 were detected in 19.5% (n=282) of women. Age-specific prevalence of HPV showed a plateau-shaped curve. Conclusions. The prevalences of HPV infection and abnormal cytology were much higher than previously reported in general populations in South Africa and elsewhere. Higher age-specific prevalence and similar plateau-like age-specific epidemiological curves have previously only been described in studies among HIV-positive women. These findings have implications for planning and development of cervical screening programmes in developing countries with largely unscreened populations with a high background prevalence of HIV. Specimen collection and testingAll participants were screened with conventional cytology (Pap smear) as per national protocol. Cytopathology reports were based on the Bethesda system. [13] Specimens for HPV genotyping were either healthcare worker-collected dry cervical swabs (N=951) or patientcollected tampon specimens (N=573). Tampons were placed in a phosphate buffered saline and 10% methanol solution directly after collection. DNA extraction was performed in batches on washed cell pellets of the tampon specimens or directly on the dry swab specimens using the DNA Isolation Kit (Roche Molecular Systems, Branchburg, NJ) on the MagNA Pure automated extraction system. HPV genotyping was done using the HPV linear array (LA) genotyping kit (Roche Molecular Systems, Branchburg, NJ). The pool of primers is designed to amplify HPV DNA from 15 high-risk genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73 and 82), 3 probable high-risk genotypes (26, 53 and 66) and 19 low/undetermined-risk types (6,11, 40, 42, 54, 55, 61, 62, 64, 67, 69, 70, 71, 72, 81, 83, 84, IS39 and CP6108). The β-globin gene was amplified concurrently to assess cellular adequacy, extraction and amplification for each individually processed specimen. Strict procedures were followed to avoid contamination, with ne...

The Vaccine and Cervical Cancer Screen (VACCS) project: Linking cervical cancer screening to HPV vaccination in the South-West District of Tshwane, Gauteng, South Africa

“…DNA was extracted from the tampon specimens and tested using Roche linear array for HPV DNA testing as described previously. [6] Parents and guardians of girls aged 9 years and older in grades 4 -7 were invited to provide consent, and all girls were requested to provide consent for HPV vaccination. The vaccine was administered per protocol by a team of registered nurses during school hours.…”

Human papillomavirus DNA testing on self-collected vaginal tampon samples as a cervical cancer screening test in a Gauteng population

“…17 This trend was clearly not present in this study population, and was also reported by Richter, Becker, Horton and Dreyer. 6 Multiple factors may be responsible for why the trend is for HPV infections to persist, rather than to clear. These may include poor herd immunity against HPV, partly because of high HIV infection rates and sexual behaviour patterns.…”

“…It is expected that mortality from cervical cancer in these countries can be lowered with any screening test, provided that the necessary coverage, appropriate screening interval, as well as treatment and follow-up of screen-positive individuals can be achieved. 6 To date, the logistical challenges of a speculum and cytologybased screening programme have prevented effective implementation in most developing environments, necessitating the urgent investigation of alternatives.…”

Paradigm shift needed for cervical cancer: HPV infection is the real epidemic

“…The high burden of disease demonstrated in this study underlines the importance and urgency of HPV vaccination and screening in SA, and indicates a high expected return on investment. [9] and in the general South African population (dashed lines), as described by Richter et al [8] and unpublished data from the University of Pretoria Gynaecological Oncology Unit (2011). Th e fi gure shows trends and prevalence relative to each other rather than the absolute prevalence, so there is no vertical axis.…”

“…[8] This study, performed among women attending public sector primary healthcare clinics in the Tshwane area of Gauteng, describes the highest prevalence of hrHPV ever reported in an unselected screening population (Fig. 3).…”