Cervical human papillomavirus infection among female sex workers in southern Vietnam

Prevalence of human papilloma virus infection and risk of cervical intraepithelial neoplasia among female sex workers in Mumbai, India

Introduction

Cervical cancer, mostly caused by human papilloma virus (HPV), has disproportionately high incidence in developing countries. HPV infection being essentially a sexually transmitted infection, high-risk behaviour women with multiple sexual contacts like female sex workers (FSWs) are at higher risk of co-infection with HPV and of developing cervical precancer and cancer.

Objective

This study aimed to determine the prevalence and determinants of HPV infection and cervical intraepithelial neoplasia (CIN) among FSWs in Mumbai, India.

Methods

A cross-sectional study was conducted among 448 FSWs, between the ages of 18-50 years, by collaborating with local non-government organizations working for the health and welfare of FSW communities at sexually transmitted diseases clinics. All FSWs were screened for HPV DNA by hybrid capture II followed by reference diagnosis of colposcopy and/or cervical biopsy.

Results

The prevalence of HPV DNA positivity was 35.5% and CIN was 2.2%. Factors significantly associated with HPV DNA positivity were age group younger than 30 years odds ratio (OR = 2.098, 95% confidence interval (CI) 1.408-3.127), Illiteracy (OR = 2.015, 95% CI 1.305-3.112), being single (OR = 2.409, 95% CI 1.558-3.724), less than 18 years of age at time of initiating work as FSW (OR = 3.718, 95% CI 3.718-2.392), having more than five clients per day (OR = 2.078, 95% CI 1.301-3.318), been working as a FSW for more than 5 years (OR = 2.321, 95% CI 1.455-3.701), not using barrier contraception methods (OR = 5.155, 95% CI 3.395-7.827) and having no exposure to human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) education program (OR = 29.153, 95% CI 15.385-55.240). FSWs with a positive HPV DNA test are substantially more likely to have CIN compared to those with a negative test (OR = 7.6, 95% CI 1.59-36.25).

Conclusion

The prevalence of HPV infection and CIN was high among FSWs. FSWs with a positive HPV DNA test had a seven times higher risk of developing CIN. The persistence of HPV infection is expected to significantly raise the risk of cervical cancer in the future. It is suggested to have an integrated approach towards cervical cancer screening and HIV/AIDS control activities.

Prevalence and risk factors for human papillomavirus infection among female sex workers in Hanoi and Ho Chi Minh City, Viet Nam: a cross-sectional study

Objective

Female sex workers (FSWs) are at high risk of human papillomavirus (HPV) infections and cervical cancer due to their high number of sexual partners. The objectives of this study were to determine the prevalence of HPV and identify risk factors for high-risk HPV infection among FSWs in Hanoi and Ho Chi Minh City (HCMC), Viet Nam.

Methods

A cross-sectional study was conducted in Hanoi and HCMC between December 2017 and May 2018. We surveyed and screened 699 FSWs aged ³18 years for HPV infection and abnormal cytology. A multivariable modified Cox regression model was used to determine risk factors for high-risk HPV infection.

Results

The overall prevalence of any HPV, high-risk HPV and HPV-16/18 infection in the 699 FSWs was 26.3%, 17.6% and 4.0%, respectively, and were similar in both cities. Multiple infections were identified in 127 participants (69.0%). HPV-52 was the most prevalent (7%), followed by HPV-58 (6%). Abnormal cytology was detected in 91 participants (13.0%). FSWs who are divorced (adjusted prevalence ratio [aPR]: 1.96, 95% confidence interval [CI]: 1.01-3.81), widowed (aPR: 3.26, 95% CI: 1.49-7.12) or living alone (aPR: 1.85, 95% CI: 1.01-3.39) were associated with a higher prevalence of high-risk HPV infection.

Discussion

Almost one in five FSWs in Viet Nam are infected with high-risk HPV. This highlights the importance of prevention strategies such as HPV vaccination and screening in this high-risk group.

Efficacy of careHPV™ human papillomavirus screening versus conventional cytology tests for the detection of precancerous and cancerous cervical lesions among women living with HIV-1 in Lao People's Democratic Republic

BACKGROUND

In the Lao People's Democratic Republic (Lao PDR), cervical cancer is the third leading cause of women cancer.

AIMS

The objective of this cross-sectional study was to compare the efficacy of careHPV™ test versus conventional Pap smear or Siriraj liquid-based cytology in the detection of cervical cancer in women living with human immunodeficiency virus type 1 (HIV-1).

MATERIALS & METHODS

Overall, 631 women consented to participate. Four cervical specimens were taken for the purpose of conventional Pap smear, Siriraj liquid-based cytology, careHPV™ test, and HPV-16 genotyping. The exact McNemar test was used to compare the efficacy and diagnostic performance of the tests.

RESULTS

Of the 631 women with follow-up, 331 were human papillomavirus (HPV) negative. High-grade squamous intraepithelial lesions were found in 37 women, biopsy-proven high-grade cervical intraepithelial neoplasia in 50 women, and invasive carcinoma in seven women. The proportion of women with high-grade cervical lesion or carcinoma detected after abnormal careHPV™ test was higher (6.02%; 95% confidence interval [CI]: 4.4-8.1) than that detected by conventional Pap smear (4.59%; 95% CI: 3.2-6.5). careHPV™ and HPV-16 genotyping had, respectively, the highest sensitivity (80.8%; 95% CI: 67.4-89.5) and specificity (92.2%; 95% CI: 89.8-94.2). HPV-16 was the most frequently detected genotype.

CONCLUSIONS

careHPV™ test represents a screening option in Lao PDR, particularly in women living with HIV-1 because of higher prevalence of chronic HPV in this population.

Oral, genital and anal human papillomavirus infections among female sex workers in Ibadan, Nigeria

BACKGROUND

There are limited data on the epidemiology of HPV in different anatomical sites of female sex workers (FSW). We investigated the prevalence and concordance of cervical, vulval, oral and anal HPV among FSW in Ibadan, Nigeria.

METHODS

FSWs aged 18-45 years were enrolled in a cross-sectional survey. After interview and clinical examination, samples were collected from mouth, cervix, vulva and anus. HPV genotyping was done with Anyplex II 28HPV assay. Multivariable analyses were performed to explore associated risk factors and concordance of HPV infections across sites.

RESULTS

In total, 315 FSWs participated in the study with a mean age of 30-6.5 years. The prevalence of any HPV infection was 88% in the vulva, 84% in the cervix, 75% in the anus and 24% in the oral cavity. HPV 35 was the most prevalent and concordant high-risk type in the four sites. The risk factors for HPV infection by anatomic site varied.

CONCLUSION

This large study showed a high prevalence and concordance of HPV infections of cervical, vulval, oral and anal HPV among FSWs in Nigeria. The potential to acquire and transmit HPV is high in this population, and we highlighted the urgency to protect young women through HPV vaccination.

Prevalence and genotype distribution of genital human papillomavirus infection in female sex workers in the world: a systematic review and meta-analysis

BACKGROUND

Female sex workers (FSWs) are amongst the most susceptible groups to acquire human papillomavirus (HPV) infection and consequently, to develop cervical intraepithelial neoplasia and cervical cancer. This is the first systematic review and meta-analysis to provide estimates of the pooled prevalence of HPV infection and the distribution of HPV types among FSWs across the world.

METHODS

Five computerized databases were searched for relevant studies published since the inception date of databases to September 2019. The pooled HPV prevalence was calculated by the random effect model described by DerSimonian-Laird. Subgroup analysis was performed to identify the probable sources of heterogeneity. The meta-analysis was performed using the "Metaprop" function in the R package Meta.

RESULTS

Sixty-two studies involving 21,402 FSWs from 33 countries were included in this meta-analysis, and the pooled HPV prevalence was 42.6% (95% confidence interval (CI): 38.5-46.7%). HPV-16 (10.1, 95% CI: 8.2-12.5%), HPV-52 (7.9, 95% CI: 5.9-10.7%), and HPV-53 (6.0, 95% CI: 4.4-8.1%) were the most common high-risk HPV types identified among FSWs. The pooled estimated prevalence of HPV infection among FSWs before and after 2010 were slightly different, 43.6% (95% CI: 36.1-51.4%) and 41.9% (95% CI: 37.2-46.8%), respectively.

CONCLUSION

Due to the high prevalence of HPV infection, particularly with high-risk types, FSWs have a great susceptibility to the development of cervical and vaginal cancers. Furthermore, they can transmit their infection to their clients, which may result in a high prevalence of HPV and the incidence of HPV-associated malignancies among the general population.

Human papillomavirus infection and cervical dysplasia in female sex workers in Northeast China: an observational study

Background

Women having multiple sex partners are reportedly at an increased risk of HPV infection. However, the prevalence and risk factors of HPV infection in female sex workers (FSWs) vary considerably across racial/ethnic, socioeconomic, and geographic groups. This study aimed to determine the prevalence and risk factors of HPV infection in FSWs in Northeast China.

Methods

A total of 309 FSWs identified and approached through a local police office and 1000 healthy subjects from a single factor undergoing annual gynecological examinations in Shenyang were recruited. A liquid-based ThinPrep Pap test and the Hybrid Capture II-based high-risk HPV DNA test, with or without a colposcopic examination, were performed on both FSWs and control subjects. Data on HPV infection and histological and cytological lesions of the cervix were obtained and analyzed. A questionnaire survey was administered to all 309 FSWs with their socio-demographic and behavioral information collected. The association of various socio-demographic and behavioral variables with HPV infection was assessed.

Results

HPV was significantly more prevalent in FSWs (61.90 %) than in healthy control subjects (21.00 %) (P < 0.01), so were cervical lesions (P < 0.01). HPV prevalence in our sample of FSWs fell in the upper range of reported values in FSWs across different countries, and was similar to that for FSWs in the southeast Chinese city of Huzhou but higher than that for FSWs in southwest China, Guangxi, as compared with data from other studies within China. HPV infection in FSWs was significantly associated with the age at first sexual intercourse (OR 0.699, 95 % CI 0.492–0.992) and post-menopause (OR 2.928, 95 % CI 1.099–7.800) (P < 0.05).

Conclusions

FSWs are at a substantially high risk of HPV infection and cervical dysplasia development as compared with healthy control subjects in Shenyang, China. Age of first sexual intercourse and post-menopause are two independent risk factors for HPV infection in this special group of population. Intensified and coordinated efforts from government, public health sector, communities and families are needed to reduce the risk of HPV infection in this specific group of population.

Self-reported oral health, oral hygiene, and oral HPV infection in at-risk women in Ho Chi Minh City, Vietnam

OBJECTIVES

This study aimed to examine the relationships among self-reported oral health, oral hygiene practices, and oral human papillomavirus (HPV) infection in women at risk for sexually transmitted infections (STIs) in Ho Chi Minh City, Vietnam.

STUDY DESIGN

Convenience and referral sampling methods were used in a clinic-based setting to recruit 126 women aged 18-45 years between August and October 2013. Behavioral factors were self-reported. Oral-rinse samples were tested for HPV DNA of 2 low-risk and 13 high-risk genotypes.

RESULTS

A higher unadjusted prevalence of oral HPV infection was associated with poorer self-rated overall oral health (P = .001), reported oral lesions or problems in the past year (P = .001), and reported a tooth loss not because of injury (P = .001). Higher unadjusted prevalence of oral HPV infection was also associated with two measures of oral hygiene: lower frequencies of toothbrushing per day (P = .047) and gargling without toothbrushing (P = .037). After adjusting for other factors in multivariable logistic regression models, poorer self-rated overall oral health remained statistically associated with oral HPV infection (P = .042); yet the frequency of tooth-brushing per day did not (P = .704).

CONCLUSION

Results corroborate the association between self-reported poor oral health and oral HPV infection. The effect of oral hygiene on oral HPV infection remains inconclusive.

Risk factors for high-risk and multi-type Human Papillomavirus infections among women in Ho Chi Minh City, Vietnam: a cross-sectional study

Background

Concurrent infection with multiple types of Human Papillomavirus (HPV) is associated with an increased risk of cervical cancer; yet, little is known about risk factors for concurrent HPV infection in Vietnam. This study investigated the prevalence of and risk factors for high-risk-type HPV and multi-type HPV infections among women in Ho Chi Minh City, Vietnam.

Methods

Data were collected from a population-based survey of 1,550 women (mean age = 42.4; SD = 9.5), using a multi-stage sampling process. Socio-demographic and behavioral variables were obtained by self-report. HPV genotypes in cervical specimens were identified using PCR protocols.

Results

The prevalence of any high-risk HPV infection was 9.0%, and of multi-type HPV infection was 1.9%. In the HPV+ subsample, the percentage of high-risk HPV was 84% and of multi-type HPV was 20%. All multi-type HPV infections were high-risk-type. Lifetime smoking and older age of first sex were significantly associated with any high-risk and multi-type HPV infections. Regular condom use was inversely associated with high-risk and multi-type HPV infection.

Conclusions

Risk factors for high-risk and multi-type HPV infections were similar. Further research and intervention are needed to reduce HPV infections in order to prevent HPV-related cancers.

Cervical HPV Infection in Female Sex Workers: A Global Perspective

Introduction:

Approximately 291 million women worldwide are HPV DNA carriers. Studies have indicated that having multiple sexual partners may lead to higher HPV transmission. Thus female sex workers (FSWs) may be at greater risk of infection compared to the general population. Herein we review publications with data on FSW cervical HPV test results. We also examine variations of HPV prevalence and risk behaviors by region. Knowledge of prevalent HPV types in FSWs may lead to improved prevention measures and assist in understanding vaccination in high-risk groups.

Methods:

We conducted a review of the literature by searching PUBMED using the terms “prostitution” or “female sex workers”, “human papillomavirus” or “HPV”, and “prevalence” or “PCR” to find articles. We excluded studies without HPV testing or HPV type specific results, or unconventional HPV testing.

Results:

A total of 35 peer-reviewed publications were included in our review. High risk HPV types 16 and 18 ranged from 1.1-38.9‰ in prevalence. In addition to high-risk HPV types, newer studies reported non-carcinogenic HPV types also of high prevalence. The most prevalent HPV types reported among FSWs included HPV 6 (11.5%), 16 (38.9%), 18 (23.1%), 31 (28.4%), 52 (32.7%), and 58 (26.0%).

Conclusions:

Female sex workers have an overall high prevalence of HPV infection of high-risk types as evident through various testing methods. FSWs are thought to be at increased risk of cervical cancer because of high HPV exposure. This highlights the need for HPV and cervical prevention campaigns tailored to FSWs.

Prevalence and genotype distribution of cervical human papillomavirus infection among female sex workers in Asia: a systematic literature review and meta-analysis

Cervical human papillomavirus (HPV) infection is highly transmissible. Although there are many studies on HPV infection in general population of women globally, little attention has been paid to female sex workers (FSWs) in Asia. In this study, we used a meta-analytic approach to systematically analyse the literature to elucidate the prevalence and genotype distribution of cervical HPV infection among FSWs in Asia. Fourteen eligible studies were identified in five databases, and data including 4198 FSWs from nine Asian countries were aggregated. Crude estimates of cervical HPV prevalence among FSWs in this region ranged from 12.8% to 84.8%. FSWs had a nearly 10-fold risk of HPV infection than the general population of women. Stratified analysis showed that HPV prevalence was higher in East Asia than other subregions and in younger FSWs than older FSWs. HPV genotype distribution was statistically different between East Asia and South-east Asia. In East Asia, the most prevalent genotypes were HPV 16 (23.9%), 18 (11.0%), 58 (9.4%), 56 (6.3%) and 52 (5.3%), while they were HPV 52 (12.9%), 16 (8.5%), 58 (5.2%), 18 (5.0%) and 66 (4.9%) in South-east Asia. HPV 31, 33 and 35 were less frequently found in both subregions. HPV infection was substantial among FSWs in some Asian countries. More studies are necessary to illustrate the overall picture of HPV infection in this region.

Cervical human papillomavirus infection among young women engaged in sex work in Phnom Penh, Cambodia: prevalence, genotypes, risk factors and association with HIV infection

Background

Although cervical cancer is the leading cancer in Cambodia, most women receive no routine screening for cervical cancer and few treatment options exist. Moreover, nothing is known regarding the prevalence of cervical HPV or the genotypes present among women in the country. Young sexually active women, especially those with multiple sex partners are at highest risk of HPV infection. We examine the prevalence and genotypes of cervical HPV, as well as the associated risk factors among young women engaged in sex work in Phnom Penh, Cambodia.

Methods

We conducted a cross-sectional study among 220 young women (15–29 years) engaged in sex work in different venues including brothels or entertainment establishments, and on a freelance basis in streets, parks and private apartments. Cervical specimens were collected using standard cytobrush technique. HPV DNA was tested for by polymerase chain reaction (PCR) and genotyping using type-specific probes for 29 individual HPV types, as well as for a mixture of 10 less common HPV types. All participants were also screened for HIV status using blood samples. Multivariate logistic regression analyses were conducted to assess risk factors for any or multiple HPV infection.

Results

The prevalence of cervical HPV 41.1%. HPV 51 and 70 were the most common (5.0%), followed by 16 (4.6%), 71 (4.1%) and 81 (3.7%). Thirty-six women (16.4%) were infected with multiple genotypes and 23.3% were infected with at least one oncogenic HPV type. In multivariate analyses, having HIV infection and a higher number of sexual partners were associated with cervical HPV infection. Risk factors for infection with multiple genotypes included working as freelance female sex workers (FSW) or in brothels, recent binge use of drugs, high number of sexual partners, and HIV infection.

Conclusions

This is the first Cambodian study on cervical HPV prevalence and genotypes. We found that HPV infection was common among young FSW, especially among women infected with HIV. These results underscore the urgent need for accessible cervical cancer screening and treatment, as well as for a prophylactic vaccine that covers the HPV subtypes present in Cambodia.

HPV genotype distribution in cervical intraepithelial neoplasia among HIV-infected women in Pune, India

Background

The distribution of HPV genotypes, their association with rigorously confirmed cervical precancer endpoints, and factors associated with HPV infection have not been previously documented among HIV-infected women in India. We conducted an observational study to expand this evidence base in this population at high risk of cervical cancer.

Methods

HIV-infected women (N = 278) in Pune, India underwent HPV genotyping by Linear Array assay. Cervical intraepithelial neoplasia (CIN) disease ascertainment was maximized by detailed assessment using cytology, colposcopy, and histopathology and a composite endpoint.

Results

CIN2+ was detected in 11.2% while CIN3 was present in 4.7% participants. HPV genotypes were present in 52.5% (146/278) and ‘carcinogenic’ HPV genotypes were present in 35.3% (98/278) HIV-infected women. ‘Possibly carcinogenic’ and ‘non/unknown carcinogenic’ HPV genotypes were present in 14.7% and 29.5% participants respectively. Multiple (≥2) HPV genotypes were present in half (50.7%) of women with HPV, while multiple ‘carcinogenic’ HPV genotypes were present in just over a quarter (27.8%) of women with ‘carcinogenic’ HPV. HPV16 was the commonest genotype, present in 12% overall, as well as in 47% and 50% in CIN2+ and CIN3 lesions with a single carcinogenic HPV infection, respectively. The carcinogenic HPV genotypes in declining order of prevalence overall included HPV 16, 56, 18, 39, 35, 51, 31, 59, 33, 58, 68, 45 and 52. Factors independently associated with ‘carcinogenic’ HPV type detection were reporting ≥2 lifetime sexual partners and having lower CD4+ count. HPV16 detection was associated with lower CD4+ cell counts and currently receiving combination antiretroviral therapy.

Conclusion

HPV16 was the most common HPV genotype, although a wide diversity and high multiplicity of HPV genotypes was observed. Type-specific attribution of carcinogenic HPV genotypes in CIN3 lesions in HIV-infected women, and etiologic significance of concurrently present non/unknown carcinogenic HPV genotypes await larger studies.

Prevalence of human papillomavirus infection among female sex workers in Bulgaria

The present study estimates the prevalence and risk factors of human papillomavirus (HPV) infection among female sex workers (FSWs) in Bulgaria. HPV DNA was detected by polymerase chain reaction (PCR) in 43.4% of FSWs. HPV16 was the most common type, found in 17.0% of samples, followed by HPV31 (9.4%). Age and smoking were associated with a significantly greater risk of being infected. The results of this study indicate that FSWs in Bulgaria are at increased risk for cervical cancer and represent an important source of HPV infection for the general population in the country. They should be considered as a priority group in cervical cancer control programmes.

Prevalence of sexually transmitted diseases in female sex workers in a city in the interior of São Paulo, Brazil

Changes in the profile of sexually transmitted diseases have increased the need for their detection, particularly where there is a concentration of individuals with risk behavior, so that diagnosis and immediate treatment can be translated in the reduction of resulting problems. The objective was to identify the prevalence of sexually transmitted diseases in female sex workers in a medium-sized city in São Paulo state. This population prevalence study was conducted in 2008 on 102 females. The prevalence was 71.6%. When considered separately and in association, the highest values found were: HPV (67.7%) and Chlamydia (20.5%). HPV typing showed oncogenic genotypes. The prevalence of syphilis was 4.0% and of trichomoniasis 3.0%. No cases of hepatitis B or gonorrhea were identified. It was concluded that the prevalence of sexually transmitted diseases in the studied group was high, since approximately two thirds of the women showed some type of disease under this classification.

High prevalence of human papillomavirus infection in the female population of Guatemala

The potential introduction of the newly licensed HPV-vaccines at affordable prices could play a central role in preventing cervical cancer in middle and low-income countries, where most of the cases occur. In spite of this, basic epidemiological data about HPV and HPV-related lesions are still scarce. To determine the prevalence of cervical abnormalities, HPV prevalence, genotype distribution and related risk factors, we carried out a cross-sectional study in a population from Guatemala that included 297 women from the general population (GP women) and 297 sex workers (SW). All participating women were interviewed and underwent a complete gynecological examination that included collection of cervical cells for cytological diagnosis, HPV DNA detection and typing by PCR methods. Cervical HPV DNA prevalence among GP women and from SW was 38.1% (95% CI: 32.5-43.8) and 67.3% (95% CI: 61.7-72.6), respectively. The prevalence of abnormal cytology among GP women was 7.7% (ASCUS = 1.4%, LSIL = 4.7%, ASC-H = 0.3% and HSIL = 1.4%) and among SW was 21.6% (ASCUS = 7.5%, LSIL = 10.6%, ASC-H = 1.4% and HSIL = 2.1%). The most prevalent HPV types among women with normal cytology were HPVs 51 (n = 30), 66 (n = 25) and 16 (n = 25), and among women with HSIL or ASC-H (n = 14) HPVs 58 (n = 5) and 16 (n = 5). Determinants associated with HPV DNA detection were having had an occasional partner during the last 6 months and smoking habit among GP women, and being a minor among SW. HPV and abnormal cytology prevalence is high among women in Guatemala. The introduction of a HPV vaccination program would prevent an important fraction of HPV-related disease burden.

Oncogenic human papilloma virus and cervical pre-cancerous lesions in brothel-based sex workers in India

A community-based cross-sectional study was conducted in brothel-based sex workers of West Bengal, Eastern India, to determine their oncogenic human papillomavirus (HPV) status and the presence of pre-cancerous lesions. A total of 229 sex workers from three districts of West Bengal participated in the study. All the study participants were interviewed with the aid of a pre-tested questionnaire to determine their sociodemographics, risk behaviour and risk perceptions after obtaining informed verbal consent. The interview was followed by collection of cervical cells from all participants using a disposable vaginal speculum and cervical cytobrush. Oncogenic HPV DNA was detected by real-time polymerase chain reaction (PCR). A simultaneous Papanicolaou test ('Pap smear') was performed to detect cervical cytological abnormalities. Overall, the prevalence of oncogenic HPV was found to be 25% (58/229) among the studied population. A subset (n=112) of the sample was tested separately to determine the existence and magnitude of HPV genotypes 16 and 18. The results showed that genotype 16 was prevalent in 10% (11/112), genotype 18 in 7% (8/112) and both genotype 16 and 18 in 7% (8/112). The HPV prevalence rate showed a decreasing trend with age, being 71.4% in the 10-19 years age group, 32.3% in the 20-29 years age group, 18.3% in the 30-39 years age group and 2.5% in the >or=40 years age group (statistically significant differences, P<or=0.00001). Considering the duration of sex work, oncogenic HPV prevalence was found to be 55% (n=21) and 19% (n=35) in sex workers with a sex working duration of <or=1 year and >1 year, respectively. This difference was found to be statistically significant both by univariate and multivariate analysis. In this study, it was observed that sex workers with an average number of daily clients of six or more had an HPV prevalence of 67% (n=6), those with four to five clients had a prevalence of 45% (n=9), those with two to three clients had a prevalence of 30% (n=34) and those with one or less clients had a prevalence of 10% (n=9) (statistically significant differences, P=0.00003). Multivariate analysis showed a statistical association only with a duration of sex work of <or=1 year [odds ratio (OR)=3.3; 95% confidence interval (CI) 1.4-7.6] and daily income of Rupees (Rp) >or=101 (OR=2.5; 95% CI 1.3-5). Regarding pre-cancerous lesions, 2 of 229 sex workers showed the presence of a low-grade squamous intraepithelial lesion along with high-risk HPV. Thus, 1% of the studied population suffer from a pre-cancerous lesion caused by high-risk HPV. This study concludes that young sex workers are particularly vulnerable to high-risk HPV, similar to human immunodeficiency virus (HIV). The observation of older sex workers relatively free from HPV supports the view of acquired immunity against HPV, which needs to be studied in-depth further. There is a need for a suitable community-based intervention programme targeted towards sex workers, with special reference to younger sex workers, for control and prevention of HPV and cervical cancer. Vaccination against HPV for newly entrant sex workers may be an important component for a successful intervention programme.