Current Issue - 2007, Volume 2 Number 2

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CURRENT ISSUES FACING THE INTRODUCTION OF HUMAN PAPILLOMAVIRUS VACCINE IN MALAYSIA

LP Wong,1 IC Sam2
1Wong Li Ping, MSc, PhD, Lecturer, Health Research Development Unit (HeRDU), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia. Tel: 603-79675738, Fax: 603-79675769, Email: wonglp@ummc.edu.my (corresponding author)
2I-Ching Sam, MRCP, MRCPath, Associate Professor, Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

Conflict of interest: none

ABSTRACT

Certain human papillomavirus (HPV) types are strongly associated with cervical cancer. Recently-described effective vaccines against these HPV types represent a great medical breakthrough in preventing cervical cancer. In Malaysia, the vaccine has just received regulatory approval. We are likely to face similar barriers to implementing HPV vaccination as reported by countries where vaccination has been introduced. Most women have poor understanding of HPV and its link to cervical cancer. Physicians who will be recommending HPV vaccines may not have extensive knowledge or experience with HPV-related disease. Furthermore, a vaccine against a sexually-transmitted infection may elicit negative reactions from potential recipients or their carers, particularly in a conservative society. Given the high cost of the vaccine, reaching the most vulnerable women is a concern. To foster broad acceptance of HPV vaccine, education must be provided to health care providers, parents and young women about the risks of HPV infection and the benefits of vaccination.
Keywords: Cervical cancer, human papillomavirus, vaccination

Wong LP, Sam IC. Current issues facing the introduction of human papillomavirus vaccine in Malaysia. Malaysian Family Physician. 2007;2(2):47-53

INTRODUCTION

In most developing countries, cervical cancer is one of the leading causes of cancer-related deaths among women.1 In Malaysia, cervical cancer is the second most common female cancer, constituting 12.9% of all female cancers.2 The Malaysian National Cancer Registry reported an average of 2,000-3,000 hospital admissions of cervical cancer per year in Malaysia, with the majority presenting at late stages of the disease.2

Cytology-based screening using the Papanicolaou (Pap) smear is the main screening method used for the secondary prevention of cervical cancer. However, only about 5% of women in developing countries are screened, compared with 40-50% in developed countries.3 In many high-resource countries, the implementation of a wide-coverage Pap smear screening programme has reduced cervical cancer incidence and mortality. In developing countries, the lack of screening due to the lack of resources, infrastructure, and technological expertise has contributed to the continued increase in the incidence of cervical cancer.4 In addition, due to the low sensitivity of the Pap test, 50% of adenocarcinomas and 25% of squamous cell carcinomas occur in adequately screened women.5 In Malaysia, cervical cancer screening coverage is poor, at <2% in 1992, 3.5% in 1995 and 6.2% in 1996.6

Possible reasons for this include uneven distribution of medical facilities throughout the country,7 lack of knowledge about the availability of screening,8 and reluctance to undergo Pap smears for cultural reasons.8 A further problem is poor sampling technique leading to inadequate smears.9

HUMAN PAPILLOMAVIRUS (HPV)

HPV is a non-enveloped, double-stranded DNA virus. There are over 100 HPV types, of which 40 typically affect the anal and genital areas (Figure 1). Thirty types are associated with cervical cancer, with the high-risk types 16 and 18 accounting for over 70% of all cases worldwide,10 including in Malaysia.11 Other less prevalent oncogenic types include types 31, 33, 45, 52, 58, and 59.10 More than 99.7% of cervical tumour specimens contain detectable HPV DNA,12 making the association between HPV infection and cervical cancer one of the strongest in cancer epidemiology. HPV types 6 and 11 are common low-risk oncogenic types, which are associated with >90% cases of genital warts.12 Transmission of HPV infection usually occurs from penetrating intercourse and genital skin-to-skin contact. Most infections are asymptomatic, transient, and have no adverse effects. Thus, transmission may occur unknowingly and infected persons are often unaware that they are carriers. As many as 75% of adults may acquire HPV infection during their lives, and the highest rates for HPV infection occur in women between 18-28 years.14 Cervical immaturity, due to factors such as metaplastic changes during puberty, may increase the susceptibility of adolescents to HPV infection.15