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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
WHISPER or SHOUT study: Efficacy of a mobile phone text messaging intervention for improving the health of female sex workers in Mombasa, Kenya.
Scientific title
Women’s Health Intervention using SMS for Preventing Unintended Pregnancy (WHISPER), or SMS intervention to improve nutritional Heath OUTcomes (SHOUT): A cluster randomised controlled trial assessing mHealth interventions among female sex workers in Mombasa, Kenya
Secondary ID [1] 289174 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Unintended pregnancy 298708 0
HIV 298710 0
Anaemia 298711 0
Nutrition 298712 0
Sexually transmitted infections 298713 0
Condition category
Condition code
Reproductive Health and Childbirth 298765 298765 0 0
Infection 298766 298766 0 0
Acquired immune deficiency syndrome (AIDS / HIV)
Blood 298767 298767 0 0

Study type
Description of intervention(s) / exposure
Mobile phone delivered health promotion intervention (mHealth intervention), addressing contraceptive options and their effectiveness and safety, and improvements in sexual and reproductive health self-efficacy, particularly through the promotion of long-acting reversible contraceptive methods (non user-dependent) methods.

The intervention consists of three components:
- Health messages sent through a series of SMS;
- Theory-guided role model stories sent in text message instalments, promoting positive norms and attitudes, and increased self-efficacy for healthier behaviour;
- On-demand system in which participants reply to texts free of charge to obtain more detailed information via SMS,

Messages will be delivered from an online platform and sent 2-3 times per week for one year. The messages sent and received by participants will be tracked to ensure the system is functioning as planned, and to monitor participant engagement with the system.
Intervention code [1] 294699 0
Intervention code [2] 294700 0
Comparator / control treatment
Equal-attention control consisting of a parallel mHealth intervention addressing positive knowledge, attitudes and practices regarding locally applicable actions, which could improve nutritional status of women of childbearing age.

The parallel nutrition intervention will have the same three mobile phone-based components, with identical structure, duration, and message number and frequency.
Control group

Primary outcome [1] 298376 0
Incidence of unintended pregnancy.
Pregnancy will be measured by urine pregnancy test at baseline and 6- and 12- months' follow-up, as well as self-reported during the interval since last test.
Intention will be assessed using the London Measure of Unintended Pregnancy (validated questionnaire scale) for any pregnancy that occurs during the trial.
Timepoint [1] 298376 0
6 and 12 months
Primary outcome [2] 298377 0
Prevalence of anaemia
This will be measured by laboratory-based full haemogram at baseline and 12 months.
Timepoint [2] 298377 0
12 months
Secondary outcome [1] 323973 0
Use of modern contraceptive methods and condoms consistently (dual protection) in past month with all partner types.
This will be assessed by self-report during study questionnaire at baseline and 6- and 12-month follow-up visits.
Timepoint [1] 323973 0
6 and 12 months
Secondary outcome [2] 323974 0
Current use of long-acting reversible contraceptive methods (contraceptive implant or intra-uterine device).
This will be assessed by self-report during study questionnaire at baseline and 6- and 12-month follow-up visits.
Timepoint [2] 323974 0
6 and 12 months
Secondary outcome [3] 323975 0
Incidence of induced abortion
This will be assessed by self-report during study questionnaire at 12-months. Participants who have become pregnant during the study will be asked about the outcome of the pregnancy, including induced abortion.
Timepoint [3] 323975 0
12 months
Secondary outcome [4] 323976 0
Mean haemoglobin level (g/dL).
This will be measured by laboratory-based full haemogram at baseline and 12 months.
Timepoint [4] 323976 0
12 months
Secondary outcome [5] 323977 0
Prevalence of malnutrition: either underweight (BMI < 18.5kg/m2) or overweight (BMI greater than or equal to 25 kg/m2).
Timepoint [5] 323977 0
12 months
Secondary outcome [6] 323978 0
Median score in nutrition knowledge.
This will be assessed by study questionnaire at baseline and 6- and 12-month follow-up visits, containing nutrition-related true/false knowledge statements.
Timepoint [6] 323978 0
6 and 12 months
Secondary outcome [7] 323979 0
Prevalence of healthy eating behaviour.
This will be assessed by study questionnaire at baseline and 6- and 12-month follow-up visits, containing self-reported dietary intake in previous 7 days.
Timepoint [7] 323979 0
6 and 12 months
Secondary outcome [8] 323980 0
HIV incidence
HIV will be measured by rapid diagnostic tests (Determine (Registered Trademark) HIV-1 and First response (Registered Trademark) HIV-1 rapid tests) at baseline and 6- and 12-month follow-up visits.
Timepoint [8] 323980 0
6 and 12 months
Secondary outcome [9] 323981 0
Syphilis incidence
This will be assessed by syphilis screening using rapid plasma reagin test at baseline and 6- and 12-month follow-up visits.
Timepoint [9] 323981 0
6 and 12 months

Key inclusion criteria
- Self-report engaging in paid sex work in the last six months
- Have a personal mobile phone with Safaricom or Airtel subscription, and be willing to provide the number to the researchers
- Self-report being ‘SMS literate’
- Not currently pregnant or planning pregnancy within 12 months
- Reside, and plan to continue to reside, within the site-specific catchment area for the next 12 months
- Willing to provide reliable contact information (e.g. home address) to be contacted by a member of the research team in the community
- Able and willing to give written informed consent for enrolment in the study.
Minimum age
16 Years
Maximum age
34 Years
Can healthy volunteers participate?
Key exclusion criteria
- Planning to travel or relocate from the study areas
- Participating in another mHealth intervention study
- Having a medical or non-medical issue incapacitating participation in the research, as decided by the local Principal Investigator.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation of clusters to intervention arms will be done by central randomisation by computer. Allocation will be concealed from the study team and participants until after cluster enrolment is completed and all baseline questionnaires administered for that cluster.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?

Intervention assignment
Other design features
Cluster-randomised: each sex work venue constitutes one cluster, with up to 10 participants per cluster.
Type of endpoint(s)
Statistical methods / analysis
Primary analysis will compare the primary endpoints (either unintended pregnancy incidence, or anaemia prevalence) between groups at 12 months and secondary analysis will compare groups at 6 months.
The sample size was calculated to obtain sufficient power to detect a 37% relative reduction in annual unintended pregnancy incidence, based on estimated pregnancy incidence in this population of 27%. This results in a sample size of 860 participants from a minimum of 86 clusters – 430 participants per arm. This estimate is calculated with 80% power and 5% significance level), and is adjusted for an expected 10% attrition rate and estimated inflation in standard error due to cluster randomisation.
Given the interval-censored nature of unintended pregnancy incidence, discrete-time survival models using generalised linear modelling will be used to compare unintended pregnancy incidence between FSW exposed to SRH intervention and those exposed to nutrition intervention messages.
These analyses will provide estimates with robust standard errors for FSW venue clustering. Standardised probability weighting will be applied in population-averaged analyses to account for any sampling bias where achieved sample cluster sizes vary. Where randomisation is not effective in removing allocation bias, adjusted models will be specified. In all analyses, associations will be considered statistically significant at the 5% level. The statistician will conduct the analysis blind to the intervention group.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 7890 0
State/province [1] 7890 0
Mombasa, Coast Province

Funding & Sponsors
Funding source category [1] 293642 0
Government body
Name [1] 293642 0
National health and medical research council
Address [1] 293642 0
Level 1
16 Marcus Clarke Street
Canberra ACT 2601
Country [1] 293642 0
Primary sponsor type
Burnet Institute
85 Commercial Road
Melbourne VIC 3004
Secondary sponsor category [1] 292476 0
Name [1] 292476 0
Address [1] 292476 0
Country [1] 292476 0

Ethics approval
Ethics application status
Ethics committee name [1] 295078 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 295078 0
Ethics committee country [1] 295078 0
Date submitted for ethics approval [1] 295078 0
Approval date [1] 295078 0
Ethics approval number [1] 295078 0
CF16/1552 - 2016000812
Ethics committee name [2] 295079 0
Kenyatta National Hospital ethics and research committee
Ethics committee address [2] 295079 0
Ethics committee country [2] 295079 0
Date submitted for ethics approval [2] 295079 0
Approval date [2] 295079 0
Ethics approval number [2] 295079 0

Brief summary
WHISPER is a mobile phone-based health promotion (mHealth) intervention in which text messages will be sent to female sex workers in Mombasa, Kenya. The messages address pregnancy prevention and other sexual and reproductive health (SRH) topics, including HIV/ STI prevention and gender based violence, to improve participants’ knowledge and encourage them to adopt healthier behaviours. The intervention will be tested in a randomised controlled trial to determine whether it results in fewer unintended pregnancies.

The participants receiving the WHISPER messages will be a compared to a second group receiving messages about nutritional health (the SHOUT intervention). Topics include nutritional needs, particularly iron and other micronutrients, locally appropriate food preparation and purchasing tips, water sanitation and hygiene, and food safety. The aim is to improve nutrition and reduce iron deficiency anaemia, and the rate of anaemia will be compared between the SHOUT and WHISPER groups. In other words, each intervention acts as the control group for the other.

The messages for both groups are based on health promotion theory and consultation with FSWs in Mombasa to make them relevant, engaging and effective. As well as simple stand-alone texts, participants will receive stories about sex workers in similar circumstances, overcoming familiar challenges and barriers in order to change their behaviour – for example by using more effective long term contraceptive methods or eating a greater diversity of freshly foods. Participants will also be able to text into the system to request further information via automated response codes, without bearing the cost.

The project is a collaboration between the International Centre for Reproductive Health (ICRH, Kenya) and the Burnet Institute, along with collaborating investigators from other institutions. ICRH is a local NGO with a long history of providing services and support to FSWs via outreach and drop-in clinics in Mombasa, including STI/HIV testing, pregnancy testing, counselling, and support for sexual and gender-based violence. ICRH has a respected role in the sex work community in Mombasa, and close links with other local community-based organisations working with FSWs.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 65734 0
A/Prof Stanley Luchters
Address 65734 0
Burnet Institute
85 Commercial Rd
Melbourne VIC 3004
Country 65734 0
Phone 65734 0
Fax 65734 0
Email 65734 0
Contact person for public queries
Name 65735 0
A/Prof Stanley Luchters
Address 65735 0
Burnet Institute
85 Commercial Rd
Melbourne VIC 3004
Country 65735 0
Phone 65735 0
Fax 65735 0
Email 65735 0
Contact person for scientific queries
Name 65736 0
A/Prof Stanley Luchters
Address 65736 0
Burnet Institute
85 Commercial Rd
Melbourne VIC 3004
Country 65736 0
Phone 65736 0
Fax 65736 0
Email 65736 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
Study protocol
How or where can supporting documents be obtained?
Type [1] 1164 0
Study protocol
Citation [1] 1164 0
Link [1] 1164 0
Email [1] 1164 0
Other [1] 1164 0
Attachment [1] 1164 0
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary