Download - Fern Terris-Prestholt, Lilani Kumaranayake, Catherine MacPhail, Helen Rees, Charlotte Watts
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Determinants of South African Women’s Demand for New Barrier Methods and their Distribution:
Analysis of a Discrete Choice Experiment
Fern Terris-Prestholt, Lilani Kumaranayake,
Catherine MacPhail, Helen Rees, Charlotte Watts
London School of Hygiene & Tropical Medicine
Reproductive Health and HIV Research Unit, Johannesburg
IAEN August 1-2, 2008, Cuernavaca
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Background 1
Existing products for HIV prevention are failing to provide women with a means to protect themselves from HIV.
Male condom use remains subject to consent and active participation from men.
This study explores women’s demand for new barrier methods for HIV
prevention that women can initiate, and how distribution and promotion strategies can
facilitate their use.
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Barrier methods for HIV prevention:
Existing methods Male condoms Female condoms (though not widely available)
Potential new methods Microbicides Diaphragm
Microbicide applicator containing clear gel
Diaphragm
Female Condom
Male Condom
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Aims 1: product attributes
Policy-makers are concerned about substitution
This study explores how preferences for products vary by: The product characteristics,
their effectiveness in preventing HIV Women’s characteristics
women’s risk /need profiles and their ability to use male condoms
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Aims 2: distribution & promotion strategies
Once an effective microbicide is found, it is critical to ensure women who need them can access them and introduce them into their relationships.
This study explores if: new barrier methods need different distribution and
promotion strategies from the existing methods distribution strategies need to be tailored to reach
different groups of women.
Aim 1 & 2 → to inform the introduction and distribution strategy of new methods.
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Data collection
Survey
In three township communities in Johannesburg
1017 sexually active adult women (18-45)
October 2005
Questionnaire included: demographics, reproductive health histories, directly elicited preferences, and two discrete choice experiments
Physical attributes choice
CHOICE Attribute
A B C
Izinto Product
Female condom
Microbicide
Ngasese Secrecy
X No, Cannot be
used without your partner knowing
Yes, Can be used
without your partner knowing
Ukwehlisa amathuba okukhulelwa Pregnancy risk reduction
95% reduction in pregnancies
1 of 20 women
becomes pregnant
95% reduction in pregnancies
1 of 20 women
becomes pregnant
Ukwehlisa amathuba okusuleleka nge HIV HIV risk reduction
95% risk reduction
19 of 20 women
remain HIV negative
35% risk reduction
7 of 20 women
remain HIV negative
Intengo Price
20 Rand
20 Rand
Ngeke
ngiguquke
kulokhu
bengikwenzile
esikhathini
esedlule
Neither,
I would not
change
what I did
last time
CHOICE
Front Back
Flesh to Flesh
Use no barrier method
Male Condom
Yes, Can be used without your partner
knowing
X No, Cannot be used without your partner
knowing
Does not prevent
pregnancy
All 20 women
become pregnant
95% reduction in pregnancies
1 of 20 women
become pregnant
0 risk reduction
0 f 20 women remain HIV
negative
95% risk reduction
19 of 20
women remain HIV negative
6 choice sets:
Here are the products and this is what they do:
Would you have used either of these products in your last sex act or would you have still done the same as you did the last time you had sex?
Neither option card
Distribution and promotion strategy choice
CHOICE Attribute
A B
E fumaneha kae
Distribution channel
Spaza shop
Clinic
Mokgwa wa ho lata
Collection method
In a private room
From a person
behind a counter
Molaetsa o mo paketeng
Message on package
Extra Pleasure
HIV Prevention Hlwahlwa
Price
Free, 0 Rand
10 Rand CHOICE
Which of these ways would you prefer to collect your product? Other levels included:
Chemist Supermarket
From a shelfFrom a box or dispensing machine
Pregnancy prevention Women’s empowerment
5 Rand20 Rand
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Estimation 1: physical attribute preferences
Nested LogitStructure:
Main effects: Prob=f(Product, HIV effec, Preg effec, secrecy, price)
Plus
Interactions level 1 (Change, not-change): Not change means use a male condom or use no condom (q104), Having had difficulties using a male condom in the past (q103), Cohabiting (q49) and
Interactions 2 (between products profiles): Product * used condomSecrecy* had difficultiesPregnancy effectiveness * cohabitHIV effectiveness * self perceived risk (RISK)HIV effectiveness * cohabitPrice * employment status
Change Not –change (C)condom or no condom
A BProduct profiles
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Estimation 2: Distribution strategy preferences
MNL with interactions for: new products (microbicide and diaphragm) socio demographic characteristics (cohabiting, household
SES, employment status)
Prob=f( Source, Collection method, Advert, Price)
Clinic Private room HIV prevention Free
Pharmacy Person behind counter Pregnancy prevention 5
Supermarket Box/dispensing machine Enhanced Pleasure 10
Spaza Shelf Women’s empowerm. 20
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Women’s characteristics N=1017
Condom used at last sex-act (q104) 31%
Cohabiting with sexual partner (q149) 55%
Ever experienced difficulties getting partner to use condoms (q103) 38%
Employed (emplyd) 35%
Self-perceived risk of HIV (RiskH) 23%
(RiskM) 27%
(RiskL) 24%
(RiskNo) 27%
Mean age 31.5 years
Education 45% started but did not complete secondary school
What are women’s relative preferences for new barrier methods and how do these differ by women’s characteristics? Nested Logit
Coeff.
Main effects Diaphragm (DG) 0.126 ***Microbicide (MD) 0.257 ***
Female condom (FEMC) - 0.383 *** Secrecy (SECR) 0.071 ** Pregnancy prevention effectiveness (PRG) 1.383 *** HIV prevention effectiveness (HIV) 3.605 *** Price (PRC) - 0.121 ***Interactions DG*Used condom 0.146 *** BMD*Used condom - 0.048 BFEMC*Used condom - 0.098 ** BSECR*Difficulties using condom 0.101 *** BPRG*Cohabiting - 0.144 BHIV*RISK 0.496 *** HIV*Cohabiting - 0.334 ** PRC*employed 0.044 ***Not Change Not change (C) 0.904 *** C* used condom 0.614 *** C*Difficulties using condom - 0.251 *** C*Cohabiting - 0.136 **Inclusive Value SWITCH 0.412 ***
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Probability of choosing a microbicide with different characteristics over a female condom or neither
0
10
20
30
40
50
60
70
Lowest(HIV 35%,Preg 0%,
R20)
HIV 35%,p=10
HIV 55% HIV 75% HIV 95% Preg 95% Highest (HIV 95%,Preg 95%,
R0)
Cho
ice
prob
abili
ties
(%)
Used a condom Had not use a condom
Interactions None Products Women's characteristics DGM MCD Cohabit SES Emplyd
Source Clinic 0.29 *** Pharmacy 0.33 *** Spaza (corner store) -0.43 *** +Supermarket -0.20 *** Collection method Box or dispensing machine 0.04 + +A person behind a counter -0.18 *** --- ++ In a private room 0.11 ** -A shelf 0.02 Advertising message HIV prevention 0.10 ** -- Pregnancy prevention 0.06 + +++Enhanced pleasure -0.30 *** ++
Women’s empowerment 0.13 *** + -- ++
PRICE -0.04 *** ---
-/+ is significant at a P-value<0.1, --/++ at a P-value<0.05, and ---/+++ at a P-value<0.01. Note: From 3 separate regressions
What are women’s relative preferences for distribution strategies?
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Preferences for advertising messages
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
None Diaphragm Microbicide Cohabiting SES Employed
Rel
ativ
e ut
ilitie
s
HIV prevention Women’s empowerment Enhanced pleasure Pregnancy prevention
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Challenges to analysis
Potential Biases: ‘in the last sexact’: Many women responded based on best
intentions in the possible future, rather than realistic and feasible option in last sexact.
Orthogonality: The trade off between a strictly orthogonal experimental design and realism: less than efficient design non convergence of more sophisticated models : e.g. RPL with
correlations which would allow for identification of distribution strategy attributes.
HIV effectiveness very dominant attribute: 35% always chose alternative with highest HIV effectiveness
However, despite shortcomings appear to generate intuitive results.
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Conclusions- physical attributes
Encouraging to see greater enthusiasm for switching to new products among women who are less able to protect themselves with existing methods: Women who are not using condoms Have had difficulties using condoms and Are cohabiting.
Product effectiveness clearly played an important role in women’s choices Hierarchical messages should work to help women
choose the best options for them in their situations in this population.
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Conclusions – distribution attributes
Outlet type had strongest impact on choices but did not vary much by product or women’s characteristics: Do not need new infrastructure to distribute
new products or reach different women Advertising preferences do vary by product and
women’s characteristics: Advertising can be used to stimulate demand of
different products by different women. Suggests a social marketing approach may be
successful.
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Acknowledgements This study was supported by
funding from the DFID/MRC Microbicides Development Programme. UK Department for International Development (DFID). DFID supports policies, programmes and projects to promote international development. DFID provided funds for this study as part of that objective but the views and opinions expressed are those of the authors alone.
FTP, LK, HR, CW are members of the DFID Research Programme Consortium for Research and Capacity Building in Sexual and Reproductive Health and HIV in Developing Countries.
We thank all the women of Ekurhuleni
who participated in the survey and the formative qualitative research and
the enthusiastic research team who spent many an evening and weekend interviewing women.