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Ministry of Education and Training Ministry of Health
National Institute of Epidemiology and Hygiene

PHAM THI MINH PHUONG
HIV AND SEXUALLY TRANSMITTED INFECTIONS IN FEMALE SEX WORKERS
IN 4 DISTRICTS OF HA NOI AND THE EFFECT OF SOME INTERVENTION
ACTIVITIES
Specialization: Epidemiology
Code: 62 72 01 17
ABSTRACT OF PhD DISERTATION
Ha Noi - 2014
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The work is completed in:
National Institute of Epidemiology and Hygiene
Thesis advisor:
1. Ass.Prof. TRẦN HẬU KHANG, PhD
2. Ass.Prof. NGUYỄN ANH TUẤN, PhD
Opponent 1: Prof. Dao Van Dung, PhD
The Central Department of Propaganda and training
Opponent 2: Ass. Prof. Ho Ba Do, PhD
The Military Medical Insitute
Opponent 3: Ass. Prof. Tran Dang Quyet PhD
The Military Medical Insitute
The thesis will defensed at Institutional commitee in National Institute of Epidemiology and Hygiene
at , date month year
Full disertation could be found at
- National Library
- The library of National Institute of Epidemiology and Hygiene
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Scientific articles published

FSW Female sex worker
HCM City Ho Chi Minh City
HIV Human Immunodeficiency Virus
PCR Polymerase Chain Reaction
RPR Rapid Plasma Reagin
STI Sexually Transmitted Infection
TPHA Treponema Pallidum Haemagglutination Assay
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female sex workers in 4 districts of Ha Noi and the effect of some
intervention activities” was implemented.
2. Study objectives:
− To describe the HIV/STI situation and related factor among
FSW in 4 districts of Ha Noi 2005 – 2006.
− To evaluate the effectiveness of some HIV/STI control
intervention activities in FSW in Ha noi 2005-2010.
3. New findings of the dissertation
The dissertation has provided new information about HIV/STI
prevalence of FSW in 4 districts in Ha Noi at 2005-2006 and at 2009-
2010 and about HIV/ Chlamydia infection related factors among FSW at
2005-2006. The dissertation has also evaluated some intervention
activities aiming to HIV/STI control in FSW group.
4. Scientific and confident issue in the thesis
The study used quasi-experimental study with pre and post
intervention comparison. The sampling and sample size, data collection
instrument including questionnaire and laboratory tests, data analysis
were relevant, thus the results are scientifically confident.
5. Outline of the dissertation
The dissertation is 123 page length excluding table of content, list
of tables, list of figures, appendix and 131 references. The dissertation
includes: introduction, literature review, methodology, results,

Gonorrhea: Gonorrhea prevalence in FSW in Yunnan (China) was
37.8%, in Cambodia was 12%, in Indonesia was 28.6%. In Viet Nam,
gonorrhea prevalence was 3% in Ha Noi, 0.5% in HCM city, 5.3% in Hai
Phong, 20.2% in Lai Chau, 24.8% in Quang Tri, 7.3% in Dong Thap,
5.7% in An Giang, 9.4% in Kien Giang and 14.9% in Soc Trang.
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Syphilis: Syphilis prevalence in FSW was 8% in Quang Dong,
2.3% in Cambodia. In Viet Nam, the prevalence in street based FSW and
in venue based FSW was 9.1% and 7.3% in HCM city, 5.5% and 5.8% in
An Giang, 3.0% and 5.4% in Da Nang, 5.6% and 0.3% in Can Tho, 3.2%
and 2.2% in Hai Phong.
Chlamydia: Chlamydia prevalence in FSW in Yunnan (China) was
58.6%, in Cambodia was 14%. Some studies inViet Nam showed that
Chlamydia prevalence in FSW was 48.4% in Soc Trang, 5% in Ha Noi,
3.3% in Hai Phong, 3% in Quang Ninh, 6.5% in HCM city and 3.5% in
Da Nang.
1.2.2. The association between some behaviors and HIV/STI
A study in Quang Dong (2010) showed that high education level
and good STI knowledg were protective factor that could reduce the risk
of STI. The behavior of inviting clients on street or in hotel, getting more
money for selling sex was associated with higher risk of STI. According
to a study in Jamaica, age, using drug, not using condom in the last sex
were high risk behaviors of getting HIV in FSW.
A study in HCM city, Can Tho, An Giang revealed that the age
under 30, genital ucer, inconsistent condom use were associated with
higher risk of HIV. A study in Hai Phong showed that good STI
knowlegd was a protective factor while having more than 4 clients per
week, self STI treatment, poor knowlegd on condom use associated with
higher risk of STI. A study in Hue in 2008 also proved that low
education level and incorrect condom use were considered high risk

prostitution situation is complicated. Karaoke bar is one of the places of
prostitution activities. A master often hires a place to gather 10-15
FSWs, prints name cards to distribute to entertainment places such as
karaoke bars, restaurants, hotels. The heads of these entertainment places
will call the master if necessary. Each FSW carries a number for easy
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and confidential contact. Prostitution brings much profit, therefore many
entertainment places get involved in. In addition, the monitoring
activities of local authorities do not strong enough; many tourists go to
Viet Nam for prostitution leading to complicated prostitution situation.

CHAPTER 2
METHODOLIGY
2.1. Study subjects
The subjects of the study were FSWs in community of Ha Noi,
including 2 groups: street based and venue based FSW.
2.2. Place and time
The study was implemented in 4 districts of Ha Noi: Dong Da, Hai
Ba Trung, Thanh Xuan, Cau Giay.
Study was carried out from 2005 -2010. Pre intervention survey
was from 2005-2006 and post intervention survey was from 2009-2010;
Intervention was implemented from 2006-2009.
2.3. Study design
This is an quasi experimental study with pre/ post intervention
comparision. Pre intervention and post intervention survey were cross
sectional survey with cluster sampling.
2.3.1. Sample size
Formular for sample size calculation:
D = 1.3; P
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Hygiene (NIHE); Blood sample was used for HIV and syphilis detection
test at Hanoi HIV/AIDS Center.
2.5. Intervention
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Intervention activities were carried out by Women Health care
Center. The activities included STI services at the Center, mobile STI
services, counseling on HIV/STI, condom use promotion, condom and
clean syringe/needle provision.
2.6. Data analysis
EPI INFO 6.04 was used to enter data. SPSS soft ware was used for
data analysis. Descriptive and frequency analysis, T test, Chi square test,
OR and 95% confidence interval were used. The statistical significant
level of p ≤ 0.05 was used.
2.7. Bias reduction
In order to reduce the bias, investigators were experienced in public
health survey and got trained before the survey to ensure that they fully
understood their job, the objectives of the study and criteria for each
activity.
The questionnaire was developed by experienced experts and tested
to ensure it was clear, understandable for FSWs, and the answers
reflected the truth.
All of the subjects were coded, anonymous so that they felt
comfortable to give the right answers.
All of the lab test including HIV test, syphilis test and PCR for
gonorrhea and Chlamydia detection were implemented in standard
laboratory with high sensitivities and specificities. Therefore, the results
of lab tests are trustable.
2.7. Human subject
All of the subjects participated into the study voluntarily. Their
personal information was kept confidentially. The intervention activities

venue based FSW (3.7 years) (p=0,047, t test). FSWs had around 21.7
clients monthly including 14.8 irregular and 5.5 regular clients. The
number of regular and of irregular clients monthly of street based FSWs
did not different with that of venue based FSWs.
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3.1.2.2. HIV/STI knowledge of FSWs before intervention
Pre intervention study showed that 87.2% of FSW had heard about
HIV/AIDS. The proportion of FSW who considered themselves at high
risk of being HIV infected was 25.7%. That of street based FSW was
29.8%, higher than that of venue based FSW (20.5%) significantly
(p=0.018). The proportion of FSWs who had sufficient HIV knowledge
accounted for 43.1%, that of venue based FSW was higher than of street
based FSW (51.3% vs 36.4%, p=0.001).
Regarding to STI knowledge, 63.7% of FSWs recognized genital
discharge as a STI sign. Other signs such as pain at passing urine, genital
ulcers/warts and lower abdominal pain were less recognized (accounted
for 28.3%, 14.4% and 20.2% of surveyed FSW, accordingly). The
percentage of FSW who did not know any common STI signs accounted
for 17.8%. The proportion of FSW knowing 4 STI signs was 3.6%
among street based FSWs and was 0.4% among venue based FSW.
3.1.2.3. STI history of FSW in Ha Noi before intervention
Figure 3.8. STI history of FSW in Ha Noi before intervention (n=499)
According to figure 3.8, 46.5% of FSW had genital discharge and
12.8% had genital ulcer/ warts in the year before the pre intervention
survey. The history of genital discharge in the 2 groups of FSW did not
different significantly (p=0.22), but the history of genital ulcer/wart of
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venue based FSW was less than street based FSW (4% vs 20%,
p=0.0001).
3.1.2.4. Condom use bahavior of FSW in Ha Noi before intervention

clients did not inject
0.9 0.3 – 3.9 0.98
Husband/boyfriend injected vs
husband/boyfriend did not inject
1.6 0.5 – 5.5 0.47
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Related factor OR 95% CI p
Consistent condom use with irregular
clients vs inconsistent condom use
0.3 0.1 – 0.9 0.04
STI history in the last year vs no STI
history
3.3 0.9 – 11.7 0.06
Age of starting selling sex 0.9 0.8 – 1.1 0.4
Unilateral analysis showed that HIV related factors were age of
starting selling sex, being street based FSW, using drug, injecting drug,
using used needle/syringe in the last month, irregular clients injected,
husband/ boyfriend injected, having STI in the last year, inconsistent
condom use with irregular clients. These factors were put into logistic
regression to find out independent predictors. Figure 3.17 showed that
independent HIV related factors were being street based FSW, using
used needle/ syringe in the last month, inconsistent condom use with
irregular clients. Consistent condom use was protective factor. FSW who
used condom consistently during sex with irregular clients less likely to
be HIV infected (OR=0.3) than other who did not
3.1.2.5. Association between bahaviors with STI
The prevalence of gonorrhea and syphilis were very low,
therefore only Chlamydia related factors was analysed.
Unilateral analysis showed that chlamydia related factors were
being street based FSW, knowing at least 2 STI signs and buying

3.2.3. Changing in drug use bahavior
After intervention, drug use proportion did not change significantly
among street based FSW (24.4% vs 26.3%, p=0.59), but increased
among venue based FSW (from 10.3% to 18.7%, p=0.008). The
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percentage of using used needle/ syringe got decreased in both FSW
groups (in street based FSW: from 39.1% to 15.6%, p=0.01, in venue
based FSW: from 55.6% to 14.3%, p=0.05)
3.2.4. Changing of condom use bahavior
After intervention, among street based FSW, the percentage of
FSW who though condom was available at the selling sex place and who
though they could get condom within 15 minutes decreased, the number
of times they got free condoms did not improve (pre intervention: 7.1
times, post intervention: 5.4 times, p=0.08). Among venue based FSW,
the percentage of FSW who though condom was available at the selling
sex place and who though they could get condom within 15 minutes
were not different (p>0.05), the number of times they got free condoms
increased (from 3.8 times to 5.8 times, p=0.0001)
After intervention, consistent condom use with irregular clients
decreased (in street based FSW group: from 71.7% to 38.6%, p=0.0001;
in venue based FSW: from 81.2% to 45%, p=0.0001), with regular clients
also got decreased (in street based FSW group: from 56.1% to 33.1%,
p=0.0001; in venue based FSW: from 57.1% to 37.4%, p=0.0001).
Consistent condom use with husband/boyfriend did not change.

3.2.5. Changing in HIV/STI prevalence
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Figure 3.13. Changing in HIV/STI prevalence in FSW in Ha Noi
According to the figure 3.13, HIV and syphilis prevalence did not
change significantly (HIV: 16.6% vs 18.7%, p=0.38; Syphilis: 0.8% vs

This study showed that the syphilis prevalence among FSW in Ha
Noi was very low (0.8%), much lower that that of some other places
such as Cambodia (2.3%), Hai Phong (2.7%), Soc Trang (3,8%). This
might be explained by easy and cheap syphilis screening test and syphilis
treatment is cheap and effective. The antibiotic for syphilis treatment is
still very sensitive to the bacteria.
4.1.1.4. Chlamydia prevalence
Chlamydia prevalence in the pre intervention survey was 13.4 %,
was similar to the prevalence of FSW in Cambodia, (14%), lower than in
Indonesia (43,5%), in Kien Giang (17.3%), Lai Chau (16.2%), higher
than in Quang Tri (10.9%), Dong Thap (10%), An Giang (7.3%). The
difference of chlamydia prevalence between these studies may be due to
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the difference in sample taking and in risky bahavior of FSW in different
location.
4.1.2. HIV/Chlamydia related factors of FSW of Ha Noi in 2005 -
2006
4.1.2.1. Association between bahaviors and HIV
This study and some other studies found the behaviors that did not
relate to HIV. These included condom use with boyfriend, with regular
clients and STI history. Some studies found out the HIV related bahavior
similar to this study. These included being street based FSW,
inconsistent condom use with irregular clients and using used
needle/syringe. Due to low consistent condom use with clients and high
injecting drug prevalence among FSW, it is necessary to counsel and
instruct FSW to use condom consistently, atleast with irregular clients
and to avoid using used needle/ syringe.
4.1.2.2. The association between FSW behaviors and Chlamydia
infection
This study showed that independent factor related to Chlamydia

4.2.3. Effect on condom use bahavior
In our study, after intervention, consistent condom use with
husband/boyfriend did not increased, similar to the study of Ramesh
(2008), Nguyen Thanh Long (2003). Many studies showed that
intervention increased consistent condom use with client, but our study
showed that after intervention, consistent condom use with clients even
decreased. Data analysis showed that FSW knew the role of condom in
HIV/STI prevention. However, condom availability after intervention
was decreased, the percentage of FSW who carried condom at the time
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of interview was very low. The condom use negotiation skill of FSW
was not paid attention. These could lead to low condom use proportion
among FSW.
4.2.4. Effect of HIV prevalence
After our intervention, HIV prevalence did not decreased, similarly
with many studies of Nguyen Manh Cuong (2008), Hoang Duc Hanh
(2010), Nguyen Khac Hien (2010), Wariki (2012). However, many
studies showed that intervention helped to reduce HIV prevalence such
as study in Cambodia, Benin, Zaire, India and China. HIV is a life long
infection and the survival time of HIV infected person is long
(commonly longer than 5 years). Intervention may reduce HIV
incidence, but HIV prevalence may still increase due to increasing
cummulative HIV cases. Therefore, after intervention, HIV prevalence
might decrease, be stable or even increase. Intervention may reduce
incidence, but most of HIV studies only evaluated the prevalence but not
incidence, therfore the real effect of intervention on HIV incidence often
has not been fully evaluated.
4.2.5. Effect on STI prevalence
After intervention, syphilis prevalence did not decrease, similarly
to study of Nguyen Manh Cuong (2008), Stanley Luchters (2008),

CONCLUSION
1. Situation and HIV/STI related factors in FSW in 4 districts of
Ha Noi 2005-2006
1.1. HIV/STI prevalence in FSW
• HIV prevalence was very high. The prevalence of investigated
FSW was 16.6%, of street based FSW was 22.5% and of venue based
FSW was 9.4%.