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Abstract
Objectives We assessed the efficacy of a multicomponent culturally tailored HIV/STI prevention intervention programme on consistent condom use and STI incidence among foreign Thai and Vietnamese female entertainment workers (FEWs) in Singapore.
Methods We conducted a quasi-experimental pretest and post-test intervention trial with a comparison group. We recruited 220 participants (115 Vietnamese and 105 Thai) for the comparison group, followed by the intervention group (same number) from the same sites which were purposively selected after a 3-month interval period. Both groups completed a self-administered anonymous questionnaire and STI testing for cervical gonorrhoea and Chlamydia, as well as pharyngeal gonorrhoea at baseline and 6-week follow-up. The peer-led intervention consisted of behavioural (HIV/STI education and condom negotiation skills), biomedical (STI screening and treatment services) and structural components (access to free condoms). We used the mixed effects Poisson regression model accounting for clustering by establishment venue to compute the adjusted risk ratio (aRR) of the outcomes at follow-up.
Results At follow-up, the intervention group was more likely than the comparison group to report consistent condom use for vaginal sex with paid (aRR 1.77; 95% CI 1.71 to 1.83) and casual (aRR 1.81; 95% CI 1.71 to 1.91) partners. For consistent condom use for oral sex, this was aRR 1.50; 95% CI 1.23 to 1.82 with paid and aRR 1.54; 95% CI 1.22 to 1.95 with casual partners. STI incidence at follow-up was significantly lower in the intervention (6.8 per 100 FEWs) than the comparison (14.8 per 100 FEWs) group (aRR 0.42; 95% CI 0.32 to 0.55).
Conclusions This trial was effective in promoting consistent condom use for vaginal and oral sex as well as reducing STI incidence among the foreign Thai and Vietnamese FEWs in Singapore. The feasibility of scaling up the interventions to all entertainment establishments in Singapore should be assessed.
- behavioural interventions
- commercial sex
- program evaluation
- public health
- bacterial infection
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Introduction
South and Southeast Asia bear the highest burden of STIs worldwide, with male patronage of female sex workers (FSWs) being the main mode of transmission.1 In recent years, sex work has increasingly shifted from brothels to entertainment establishments (EEs).2 Female entertainment workers (FEWs) in EEs could be indirect sex workers. Other than providing non-sexual services, FEWs may offer sexual services to male patrons in EEs where transaction is likely to occur elsewhere due to the illegality of sex work in many countries.2 For example, in Singapore, a high prevalence of EEs (71%) offered sexual services, of which 53% of the FEWs reported selling sex.3 Most of these FEWs (75.4%) are on social visit passes while the rest (24.6%) are employed for non-sexual entertainment services.4
Indirect sex work in the EEs is mostly illegal with lack of access to HIV/STI prevention programmes for FEWs.5 6 Among the few HIV/STI interventions targeting FEWs, majority have focused on behavioural interventions alone.7–9 Effective HIV/STI prevention in sex work should include combinations of biomedical, behavioural and structural interventions tailored to local contexts.10 Most studies also adapted their interventions from other effective programmes.8 9 It is unclear whether these interventions would always be culturally appropriate for FEWs in their settings.8 9 In addition, the outcome effects might not be attributed to the intervention in some of these studies due to limitations in study design. They either lacked multiple pretest and post-test assessments to qualify to be a time-series design or were pretest and post-test designs involving only the intervention group.9 Most of these studies also relied only on self-reported behavioural without biomedical outcome indicators.7–9 Finally, these studies did not study oral sex or casual (unpaid) sex.7–9 Unprotected oral sex can result in HIV/STI transmission.11 Most studies have focused on paid sex although casual sex is prevalent in EEs.12 13 Till now, it is unclear whether HIV/STI interventions among the FEWs are also effective in increasing condom use for oral sex and with casual partners.
To date, almost all studies globally focused on native rather than foreign FEWs.8 9 Foreign FEWs are more vulnerable to HIV/STIs than their native counterparts due to their foreign status in the country of work, high mobility and their preference to remain hidden. Movement of foreign FEWs across countries is expected to rise with increasing globalisation and ease of travel.2 5 6 Wide income disparities have led to a movement of women from various countries to work in EEs worldwide.7 14 15 Similar to other developed countries, there has been an influx of women5 6 to work temporarily as FEWs who are beer promoters, singers, dancers, hostesses or waitresses working in or just outside the EEs in Singapore.16 A study on foreign FEWs in Singapore showed that the Thais (58.8%) and Vietnamese (56∙8%) reported lower consistent condom use than the Chinese nationals (75.9%) in 2008.3 To date, there is no regular HIV/STI prevention programme in the EE setting in Singapore. Sex work is illegal beyond registered brothels in well-delineated red-light districts locally.16 The aim of this trial was to assess the efficacy of a multicomponent HIV/STI prevention intervention programme in increasing condom use and reducing STIs among foreign FEWs in Singapore. We hypothesised that a comprehensive sexual health promotion programme with behavioural (culturally tailored HIV/STI education and condom negotiation skills using social cognitive theory), biomedical (STI screening and treatment services) and structural components (access to free condoms) delivered to foreign FEWs in Singapore would achieve an increase in consistent condom use and a reduction in STI incidence.
Methods
Trial design
This was a quasi-experimental pretest and post-test intervention trial with a comparison group. Needs assessment took place from March 2014 to February 2015. Two well-defined geographical sites where the Vietnamese and Thai FEWs worked respectively, Joo Chiat Road (in Eastern Singapore) and Beach Road (in Southern Singapore), were purposively selected. All participants completed a questionnaire and received STI testing at both baseline and 6-week follow-up. The short follow-up period is because most FEWs hold only social visit passes of 1–2 month duration and are not migrants to Singapore.5 6 The sites were first used to recruit the comparison group (March to July 2015) to prevent diffusion of intervention information. After a 3-month interval period, the same sites were used to recruit the intervention group consisting of new participants (November 2015 to April 2016).
Participants
The inclusion criteria were either a Vietnamese or Thai FEW between the ages of 18 and 69 years who was (i) planning to work for at least 6 weeks after the baseline survey in the EE setting, defined as places providing entertainment activities namely karaoke lounges, bars, pubs, nightclubs and discotheques16 in Singapore and (ii) had engaged in vaginal, oral or anal sex with either a casual or paid male partner in the past month.
Sample size, sampling method and steps taken to reduce biases
The details of the sample size calculation and the sampling method is in the online supplementary web reference 1. The recruitment process is available in the online supplementary web reference 2. Steps taken to reduce biases at the start of the study are detailed in the online supplementary web reference 3.
Supplemental material
Supplemental material
Supplemental material
Needs assessment
This consisted of in-depth interviews, observations and informal discussions with FEWs and stakeholders in the EE industry to (i) understand the needs of FEWs, including their ideas, concerns and expectations about the intervention programme; (ii) understand the FEWs’ cultural background and their preferred mode of communication; (iii) explore the reasons for non-condom usage among FEWs and (iv) develop and pilot test culturally tailored intervention materials. The reasons for non-condom use among FEWs included misconceptions on the transmission and consequences of STI/HIV, low risk perception of contracting HIV/STI from paid/casual partner, lack of skills to initiate or to persuade partner to use condom, unavailability of condoms in the EE setting and fear of the police using condom as circumstantial evidence. Findings from the needs assessment were used to inform the development of the contents and delivery of the intervention programme.
Conceptual framework for an intervention programme
We applied GREEN’s PRECEDE-PROCEED framework17 to develop the intervention programme consisting of behavioural, biomedical and structural components with integration of the following: (i) providing HIV/STI knowledge and applying social cognitive theory to equip the FEWs with condom negotiation skills—the mediating factors in consistent condom use18 (ii) adaptation from previous successful educational interventions for brothel-based FSWs in Singapore19 and (iii) needs assessment studies described earlier.
To minimise Hawthorne effect which is the alteration of behaviour due to awareness of being observed, the behavioural component of the comparison programme consisted of four sessions similar to the intervention programme. For each on-site session, groups of three to four participants were gathered for the intervention sessions in the shops whose owners were highly respected and trusted by the FEWs or at the drop-in centre operated by a non-government organisation (NGO). We trained and engaged peer educators to deliver both the intervention and comparison programmes. The overview of the intervention and comparison programme components is in the online supplementary web reference 4. The details of each behavioural session of the intervention programme are in table 1.
Supplemental material
Detailed description of each behavioural intervention session for FEWs
Primary outcome measurement
Consistent condom use for vaginal sex with paid partner in the past month was assessed by two questions: ‘Have you ever had vaginal sex in the past month?’; ‘If you have had vaginal sex, how often did you use a condom with your paid partner?’ Participants who responded ‘Yes’ to the first question and ‘Always’ to the second question were classified as having consistent condom usage for vaginal sex with paid partner in the past month. The questions on the other primary outcome of consistent condom use for vaginal sex with casual partner in the past month were identical except with replacement of ‘paid partner’ for ‘casual partner’.
Secondary outcome measurement
Apart from consistent condom use for oral sex with paid and casual partner in the last month, the other secondary outcome was STI positivity. This was defined as having at least one incident STI at 6-week follow-up, including cervical chlamydia, cervical gonorrhoea or pharyngeal gonorrhoea. The diagnoses of cervical chlamydia and cervical gonorrhoea were based on positive self-collected vaginal swabs using nucleic acid amplification testing (NAAT) by PCR. The sensitivity and specificity of self-collected swabs were equivalent to clinician-collected swabs using NAAT in a meta-analysis.20 Throat swabs collected by healthcare personnel were used to diagnose pharyngeal gonorrhoea.
Questionnaire
The follow-up questionnaire is given by the online supplementary web reference 5. The baseline questionnaire was identical to the follow-up questionnaire except in respect to the omission of the final section E (‘Feedback on Intervention Programme’). The questionnaires contained questions concerning: (i) the primary and secondary outcome measurements (questions cited in full above); (ii) factors which we presumed to have a mediating role in respect to those outcome measurements, such as HIV knowledge, condom negotiation behaviour and success of condom negotiation behaviour; (iii) sociodemographic characteristics of participants and their sexual behaviour. Consistent condom negotiation was defined as always using persuasive strategies to ask the partner to use a condom prior to the specified sex in the past month; non-condom negotiation meant never or only occasionally asking. Success in condom negotiation was defined as the partner always agreeing to use a condom in the past month when requested by the FEW; non-success meant never or occasionally agreeing. HIV knowledge was determined by the 18-item HIV Knowledge Questionnaire (HIV-KQ-18).21 Scores were summed (range: 0–18), with higher scores indicating greater knowledge.21
Supplemental material
Statistical analyses
The baseline equivalence of sociodemographic characteristics and sexual behaviour in the intervention and comparison groups were compared using χ2 test for categorical, Mann-Whitney U test for ordinal and independent samples t-test for continuous variables. Any statistically significant variable between the comparison and intervention group would be adjusted in the outcome evaluation along with the outcome at baseline. For outcome evaluation, complete data analysis (or list-wise deletion) was carried out without any imputation of missing data. Data were assessed to be missing at random. The mixed-effects Poisson regression model accounting for clustering by EE venue and calculation of robust standard errors was used to compute the crude risk ratio (RR) and adjusted RR (aRR) of the outcomes in the intervention versus the comparison group at follow-up. The default standard errors obtained by Poisson regression are typically too large; therefore, robust standard errors are needed to obtain an accurate CI around the RR.22 Poisson rather than logistic regression was used, as the outcome was common (>10% of the study population),22 since OR would likely overestimate the RR.22 For the outcome of condom use, an RR >1 indicated more participants reporting consistent condom use in the intervention than the comparison group at follow-up. All statistical analyses and sample size calculation were performed using STATA (V.14.0).
Results
A total of 440 (230 Vietnamese and 210 Thai women) out of 487 eligible FEWs (90∙3%) were recruited. Of the 440, 220 each were from the intervention and comparison groups (figure 1). At 6-week postintervention, 155 (70.5%) out of 220 successfully completed follow-up for the comparison group and 147 (66.8%) out of 220 for the intervention group.
Recruitment and follow-up.
Baseline characteristics
The intervention and comparison groups were largely similar in sociodemographic characteristics and sexual behaviour except for age and work duration (table 2). The comparison group was significantly younger (mean age: comparison, 30.0 years; intervention, 31.5 years; P=0.03) and had shorter working duration in the EE setting (mean duration: comparison, 2.0 years; intervention, 2.6 years; P=0.02) than the intervention group. Comparing those who completed follow-up and those lost to follow-up in each group, there was no statistical difference in baseline sociodemographic characteristics and sexual behaviour except for age. Those lost to follow-up were younger than those who completed follow-up in both the intervention and comparison groups. Age and work duration were not determinants of the primary and secondary outcomes in this trial.
Comparison of baseline sociodemographic characteristics, sexual behaviour and follow-up status in intervention and comparison groups
Primary and secondary outcomes
Consistent condom use for vaginal sex with paid partners increased from 44.4% at baseline to 75.0% at follow-up in the intervention compared with the comparison group where it rose from 40.4% to 41.7%. This corresponded to an aRR of 1.77 (95% CI 1.71 to 1.83, adjusted for age, working duration and baseline consistent condom use in the EE setting) at follow-up. For casual partners, this was from 50.5% at baseline to 75.3% at follow-up in the intervention as compared with the comparison group where it rose from 41.8% to 42.2%. This corresponded to an aRR of 1.81 (95% CI 1.71 to 1.91) at follow-up (table 3). The same trends were found for oral sex with paid and casual partners. The STI incidence at follow-up was significantly lower in the intervention (6.8 per 100 FEWs) than the comparison (14.8 per 100 FEWs) group (aRR 0.42; 95% CI 0.32 to 0.55). There was a moderate negative correlation in condom use with STI positivity for the intervention group at follow-up (Spearman’s rho −0.46, P<0.001).
Primary and secondary outcomes
Consistent condom use (other outcomes)
Condom use was not statistically significant with husband and steady partner for each intercourse at follow-up. For example, consistent condom use for vaginal sex with husband was 29∙2% (7 out of 24) in the intervention compared with the comparison group of 17∙6% (3 out of 17) at follow-up (P=0.48). (online supplementary web reference 6)
Supplemental material
Consistent condom negotiation behaviour and HIV knowledge (mediating factors)
Within the comparison group, there was no statistical change from baseline to follow-up in consistent condom negotiation with casual and paid partners for each intercourse (online supplementary web reference 7). Within the intervention group, there were a higher proportion of participants who consistently negotiated for condom use with casual and paid partner in vaginal and oral sex at follow-up than the baseline. For example, consistent condom negotiation increased with paid partner during vaginal sex from 44.4% at baseline to 74.2% at follow-up in the intervention (P<0.001) compared with the comparison group where it was from 43.3% to 41.0% (P=0.69). There was a strong positive correlation in condom negotiation with condom use for the intervention group at follow-up (Spearman’s rho 0.75, P<0.001). For HIV knowledge, the median score was higher at follow-up (10, IQR 7–14) compared with baseline (8, IQR 5–11) in the intervention (P<0.001) but not for the comparison group.
Supplemental material
Successful condom negotiation behaviour (mediating factors)
Successful condom negotiation behaviour was generally higher with different partner types for each intercourse in the intervention than the comparison group at follow-up. In particular, the proportion of success was higher with casual and paid partners than with husband and steady partners for each intercourse (online supplementary web reference 8). For example, the proportion of success during vaginal sex was higher with paid (94.7%) and casual partner (95.3%) than with husband (57.1%) and steady partner (52.9%) in the intervention group at follow-up. There was a strong positive correlation in condom negotiation with success for the intervention group at follow-up (Spearman’s rho 0.81, P<0.001).
Supplemental material
Discussion
The intervention group with a comprehensive sexual health promotion programme targeting Vietnamese and Thai FEWs in Singapore showed a significant increase in consistent condom use for vaginal and oral sex with paid and casual partners; and a lower STI incidence than the comparison group at a 6-week follow-up. We believe that the results were largely attributed to the intervention. There was theoretical coherence with those reporting consistent condom use in the intervention group correlating positively to condom negotiation. We took steps to minimise the influence of various biases. While those lost to follow-up could have introduced selection bias, sociodemographic characteristics and sexual behaviour did not differ significantly by follow-up status except for age, which was not a determinant of the outcomes in this trial. The results were also unlikely to be due to confounding as the intervention and comparison group were equivalent at baseline except for age and work duration, which we have adjusted for in the analysis of outcome results.
Other strengths of the trial included the use of needs assessment findings to develop culturally tailored intervention materials, careful application of sampling procedures to ensure a representative random sample, in addition to a high participation and follow-up rate so that the findings could be generalised to the Vietnamese and Thai FEWs in Singapore. The participation rate was higher compared with previous intervention studies on FEWs9 due to the use of culturally appropriate recruitment strategies (eg, provision of peer support information for their work) developed from needs assessment along with assistance of peer educators with similar sociocultural background to engage participants during recruitment. Prior to study implementation, the second author (ONYC) also volunteered with NGOs and participated in activities organised for FEWs for nearly a year. This helped build rapport and trust with FEWs, thus facilitating their participation. This trial has some limitations, one of which was the rather short follow-up time period of 6 weeks. It is unclear whether behavioural change at follow-up could be sustained over the long term. Although a longer follow–up period is preferred, it is not feasible since most foreign FEWs hold social visit passes of 1–2 months duration. Another limitation was the choice of the target group of foreign FEWs for HIV/STI prevention whose term of stay was temporary and relatively short in Singapore. However, these foreign FEWs return to Singapore regularly to engage in indirect sex work. In addition, they reported a relatively high number of paid and casual partners during their short stay.
We did not find an increase in condom use with husband and steady partner. This was similar to another trial involving FEWs in China where the intervention reported higher consistent condom use with paid partner than the comparison group at follow-up.23 Another trial involving FEWs in Malawi, Central Africa also showed that the intervention reported higher consistent condom use with paid partner in last week than the comparison group at follow-up, but not with steady partner.24 There are a few possible reasons. First, the small number who engaged in sex with these partners may have resulted in a lack of statistical power in measuring the intervention effect on these partners. Second, condom use in committed and regular relationships can be problematic because it suggests a lack of trust or implies that a partner’s HIV/STI status is suspected.25 Second, FEWs might not want to negotiate or could not apply the same strategies that they use with paid partners to that of steady partners.26 Condom negotiation could potentially disrupt the love and intimate sexual relationship with their husband and steady partner that the FEWs treasure.26
Our finding of a lower STI incidence in the intervention than the comparison group was similar to another trial involving FEWs in China.23 To break the chain of HIV/STI transmission, it is important for at least one party in a sexual relationship to be able to successfully negotiate condom use before the act. Compared with the male patrons of the EEs, it might be more pragmatic to empower the FEWs to negotiate and initiate condom use. Male patrons might not see or want themselves to be in position to negotiate and insist on condom usage particularly when they pay for sex or are under the influence of alcohol.27
Implications of study
It is important for HIV/STI programmes targeting FEWs to incorporate interventions targeting oral sex and casual partners. In the EE setting, oral sex is common and casual partner is one of the predominant sexual partners of the FEWs. This intervention programme has not only empowered FEWs with condom negotiation skills, but also facilitated the environment for condom use. Unlike brothels with 100% condom use programme, condoms are usually not available in EEs.5 6 By providing easy access to free condoms, FEWs could actively negotiate without having to buy the condoms themselves or depend on their partners or NGOs to acquire them. To have a sustaining impact on the reduction of STIs, the intervention programme could be implemented on a regular basis to the Thai and Vietnamese FEWs, as well as extended to other nationalities and eventually be scaled up to involve all the EEs at a national level. The strategies used in this trial could also be adapted for HIV/STI prevention programmes in the region and developed countries.2 9
Conclusions
In summary, this trial was effective in promoting consistent condom use for vaginal and oral sex with paid and casual partners with a corresponding reduction in STI incidence. For a sustaining impact on the reduction of STIs, the intervention programme could eventually be scaled up to involve all the EEs at a national level after assessing the feasibility.
Key messages
We developed a culturally tailored HIV/STI intervention that was effective in promoting consistent condom use among foreign Vietnamese and Thai female entertainment workers (FEWs) in Singapore.
The intervention was also effective in reducing STI incidence among the Vietnamese and Thai entertainment workers in Singapore.
For a sustaining impact on the reduction of STIs, the intervention could be scaled up to involve all the entertainment establishments at a national level.
The intervention could be adapted into HIV/STI prevention programmes for foreign Asian FEWs in the region and developed countries.
Acknowledgments
The authors would like to thank Dr Jeffery Cutter, Dr Thein Than Win, Dr Wong Pang Ong, Ms Dede Kam Tyng Tham, the Action for AIDS (AfA), the Humanitarian Organisation for Migration Economics (HOME), the Department of STI Control (DSC) Clinic, the key informants, entertainment establishment owners, the peer educators and all others who have rendered support for this study.
References
Footnotes
Handling editor Jackie A Cassell
Contributors RBTL: analysed the data, developed the tables and figures and drafted the manuscript. ONYC: was involved in data collection and data entry. BCT, MICC and RKWC: revised the manuscript critically for important intellectual content. MLW: conceptualised and designed the study as PI and revised the manuscript critically for important intellectual content.
Funding The trial was funded through the Communicable Diseases Public Health Research Grant by the Ministry of Health, Singapore (grant application number CDPHRG12NOV020).
Disclaimer The funder did not play a role in the design, conduct or analysis of the trial nor in the drafting of this manuscript.
Competing interests None declared.
Ethics approval National University of Singapore Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Raw data will not be available for sharing since we are still analysing some aspects of the data and developing other manuscripts.