Professor Caroline Free


Primary Care and Epidemiology

Keppel Street
United Kingdom

0207958 8109

Dr Caroline Free is a Professor of Primary Care and Epidemiology at the London School of Hygiene and Tropical Medicine (LSHTM), a General Practitioner and Honorary Consultant in Sexual and Reproductive Health at Kings College Hospital. She obtained her medical degree from Leeds University, an MSc from LSHTM and PhD, focussing on contraception use, from the University of London. She worked as a clinician in rural India and continues to work in south-east London providing primary, sexual and reproductive health care to an ethnically and socio-economically mixed area of London. 


Faculty of Epidemiology and Population Health
Department of Population Health


Centre for Evaluation
Centre for Maternal Adolescent Reproductive & Child Health (MARCH)



Foundations for Reproductive Health, Protocol Writing, Epidemiology and Study Design MSc modules.

Co-organiser for the distance learning module protocol writing for the MSc in Clinical trials.

Member of the examinations board for the MSc in Sexual and Reproductive Health.

PhD Supervision.

I have supervised 8 PhDs to completion and welcome applications for PhDs from potential students interested in primary health care or sexual and resproductive health intervention design and evaluation. 



Her main interest is the design, evaluation and subsequent implementation of effective primary care interventions. Several interventions focus on sexual and reproductive health. All interventions are co-developed in collaboration with potential users to ensure they are accessible and relevant across socio-econmic groups. Interventions are design based on qualitative and quantitative evidence regarding the individual, social and service level influences on health, theory and needs assessment. Where appropriate, interventions employ evidence based behaviour change approaches.

Currently she is the principal investigator for a NIHR funded trial designed to evaluate the effect of a safer sex intervention delivered by mobile phone on STI infection at one year. The trial fully recruited 6250 participants in the UK and is due to report in 2020- She is also working on an NIHR funded project for the development and pilot trial of a weight management after pregnancy intervention delivered by mobile phone. Other current work focuses on development and evaluation of interventions for primary and secondary prevention of cardiovascular disease, interventions to increase use of contraception and digital contraception services in the UK and internationally (Colombia, Palestine, Bolivia, Tajikistan, Cambodia). 

Interventions she has designed and/or evaluated have been shown to provide effective support for self-care.

She was the principal investigator for the txt2stop trial, which was the first trial to demonstrate that smoking cessation support delivered by text message more than doubled biochemically verified smoking cessation at 6 months. The intervention was found to be highly cost-effective. She worked with DH England to develop a service which has been used by 60,000-90,000 people each year since 2012. She is a adviser to the WHO m-cessation working group who have supported the development of similar services in India, Cost Rico, Philippines with several other countries are due to launch their services (e.g China, Burkina Faso and Egypt).

She was joint senior investigator for the first randomised controlled trial to reliably demonstrate that an online STI testing service (2017) increased the uptake of STI testing. The intervention was effective across socio-economic groups and among those who had never previously tested. This SH24 service is currently implemented across 22 areas in the UK and undertakes over 100,000 STI tests annually.

She is joint senior author for two Cochrane systematic reviews (due 2020) funded by WHO on the effect of targeted client communication delivered by mobile phone for maternal, neonatal and child health and sexual and reproductive health. These reviews have already informed WHO guidance. 

She is an adviser to WHO M-health working groups for non-communicable disease and the WHO advisory group for maternal, reproductive, neonatal, and child health.

She is a member of the NIHR HTA general funding board.  

Research Area
Clinical trials
Complex interventions
Health promotion
Health technology assessment
Primary care
Sexual health
Adolescent health
Behaviour change
Evidence use
Health services
Impact evaluation
Mixed methods
Mobile technologies
Reproductive health
Disease and Health Conditions
Sexually transmitted disease
Non-communicable diseases
Sexually transmitted infection
United Kingdom

Selected Publications

Can text messages increase safer sex behaviours in young people? Intervention development and pilot randomised controlled trial.
Free C; McCarthy O; French RS; Wellings K; Michie S; Roberts I; Devries K; Rathod S; Bailey J; Syred J
Health technology assessment (Winchester, England)
Simple steps to develop trial follow-up procedures.
McCarthy O; French RS; Roberts I; Free C
See more Publications