Condition category
Urological and Genital Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Chlamydia trachomatis (C.trachomatis) is the most commonly reported sexually transmitted infection (STI) worldwide. It is considered a major public health problem as it could lead to reproductive health issues such as infertility. It also increases the chances of getting the HIV infection. Secondary preventive strategies such as testing and treatment are important as they enable new cases to be detected and treated, interrupting the transmission chain. Many screening programs focus on secondary preventive strategies, alongside a varying element of prevention. Despite the recent focus on diagnosis and treatment, there has been a steady rise in infection rates among youth in Stockholm over the last two decades. However, primary preventive strategies such as condom campaigns, sexual education, and increased knowledge regarding STIs are equally, if not more, important in order to avoid new infections in the first place. A recent large population survey showed that a large number of youth reported not using a condom and did not use a condom with a new partner during their last intercourse. Staff in the Youth Health Clinics are stretched and therefore sometimes constrained with the preventive work they can do. Previous work from our research group has indicated that youth have varying level of knowledge and motivations to adopt safe sexual practices. C.trachomatis infection is highest in the youth, a group indeed familiar with and high consumers of mobile phone technology. The aim of this study is to evaluate the effects of a smart phone application to increase condom use and reduce risky sexual behaviour to see if it can be delivered to large groups of youth in Sweden and elsewhere at a low cost and support the preventive work of the screening programs.

Who can participate?
Youth aged 18 to 23 who own a smart phone and are sexually active.

What does the study involve?
Participants are randomly allocated to one of two groups. Those in the first group receive the mobile application called “"Skyddslaget”. This application provides information about sexual health and tips on a daily bases and send reminders to the users. Participants can use the application to complete challenges, quizzes, self-reflection and gain information about STIs and condom use. The application will include new activities for users. Participants in the second group receive a “dummy” or fake application. All participants are assessed before the study and again at three and six months with questionnaires to assess their sexual health habits and to compare the results between the groups.

What are the possible benefits and risks of participating?
Participants may benefit from the opportunity to reflect on their sexual behavior and this may help them engage in safe sexual practices. As sexual health is a sensitive topic, there is a risk that participants may feel uncomfortable.

Where is the study run from?
This study is being run by the Karolinska Institute (Karolinska Institutet) (Sweden) and takes place in eight youth health clinics in Sweden.

When is the study starting and how long is it expected to run for?
January 2017 to September 2018

Who is funding the study?
FORTE Swedish Research Council for Health, Working life and Welfare (Sweden)

Who is the main contact?
Mrs Anna Nielsen

Trial website

Contact information



Primary contact

Mrs Anna Nielsen


Contact details

Karolinska Institute (Karolinska Institutet)
Department of Women's and Children's Health (KBH)
Division of Obstetrics and Gynecology
Karolinska Universitetssjukhuset
+46 70 4078496

Additional identifiers

EudraCT number number

Protocol/serial number

Protocol Version 1.6

Study information

Scientific title

A parallel group, individually randomized clinical trial to evaluate the effect of a mobile phone application to improve sexual health among youth in Stockholm County



Study hypothesis

The smart phone intervention designed to promote safe sexual practices will increase condom use and therefore reduce the rate of new infections, among sexually active youth in Stockholm County.

Ethics approval

The study was approved by the Regional Ethical Board in Stockholm (EPN Regionala Etikprövningsnämnden i Stockholm), 26/08/2017, ref: 2017/651-31/4

Study design

Multicentre interventional pragmatic randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Sexually Transmitted Infection / Condom Use


Participants are individually randomly allocated to one of two groups. The randomisation allocation sequence is generated using a central computer-generated random numbers and is stratified by sex.

Intervention group: Participants receive the intervention in the form of a smart phone application called "Skyddslaget". The application delivers information and activities on a daily bases and users are reminded of the application by push-notices. The application includes things like condom-tips, self-reflections exercises, challenges, and information about sexually transmitted infections. The application will have one permanent part containing facts about STI and condoms and a second dynamic more interactive part. These include challenges and quiz, personal stories from peers, and self-rapport (elucidating ones behaviour in relation to sexual practices). Activities/information within each of these functions will be dynamic, i.e. change periodically over time such as activities. New information will be added in the application in a daily basis for 180 days. Participants are assessed at baseline and at follow up at three and six months to assess their sexual health.

Control group: Participants download a dummy application that only contains the baseline and follow-up questionnaires at three and six months.

Intervention type



Drug names

Primary outcome measures

Self-reported condom use during the past six months is measured using the assessment questionnaires at baseline, at three and six months.

Secondary outcome measures

1. Number of partners during the study period is measured using assessment questionnaires, at three and six months
2. Number of tests during the study period is measured using assessment questionnaires at six months
3. Occurrence of STI during the study period measured using assessment questionnaires at six months
4. Occurrence of pregnancy during study period is measured using assessment questionnaires at six months

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Youth aged 18-23
2. Youth who own a smart phone
3. Youth who are sexually active (had at least two partners during the past six months)
Added 16/10/2017: This criteria is to ensure youth included in the trial have recently had sex outside a stable relationship

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

Current exclusion criteria as of 05/09/2017:
1. Youth who do fulfil inclusion criteria
2. Youth who do not wish to participate
3. Women who only have sex with women will be excluded from the study as the interventions mainly focuses on safe sexual practices related to condom use

Previous exclusion criteria:
1. Youth who do fulfil inclusion criteria
2. Youth who do not wish to participate

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Södermalm ungdomsmottagning (Youth Centre)
118 46

Trial participating centre

Nacka ungdomsmottagning (Youth Centre)
131 53

Trial participating centre

Farsta ungdomsmottagning (Youth Centre)
123 47

Trial participating centre

Tyresö ungdomsmottagning (Youth Centre)
135 40

Trial participating centre

Skärholmen ungdomsmottagning (Youth Centre)
127 48

Trial participating centre

Midsommarkransen ungdomsmottagning (Youth Centre)
126 32

Trial participating centre

Järva ungdomsmottagning (Youth Centre)
164 40

Trial participating centre

Västerort ungdomsmottagning (Youth Centre)
162 61

Sponsor information


FORTE Swedish Research Council for Health, Working life and Welfare

Sponsor details

Östra Järnvägsgatan 27
101 37
+46 8 775 40 70

Sponsor type

Research council



Funder type

Research council

Funder name

Forskningsrådet om Hälsa, Arbetsliv och Välfärd

Alternative name(s)

Swedish Research Council for Health, Working Life and Welfare, FORTE

Funding Body Type

government organisation

Funding Body Subtype

government non-federal



Results and Publications

Publication and dissemination plan

The results of the trial will be published in a peer-reviewed journal. It will be of a doctoral thesis describing testing habits; sexual risk-taking and preventive strategies among youth in Stockholm County. All participants in the trial will, if they so wish, be notified about the findings after the trial period is over. Findings will also be communicated to stakeholders and policymakers in Stockholm County as well as to The Public Agency of Public Health. Finding will also be communicated to the public via media.

IPD sharing statement:
The datasets generated during and/or analysed during the current study are/will be available upon request from []

Intention to publish date


Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes

16/10/2017: The scientific title has been updated from "A parallel group randomised controlled trial to evaluate the effect of a mobile phone intervention to improve condom use among youth in Stockholm County" to "A parallel group, individually randomized clinical trial to evaluate the effect of a mobile phone application to improve sexual health among youth in Stockholm County". 05/09/2017: Exclusion criteria has been updated. Target enrolment has been updated- the small sites will recruit 44 youth (not 20 as previously stated) and the larger sites will recruit 60 youth (not 50 as previously stated).