Chlamydia is the most common sexually transmitted infection (STI) today in the United Kingdom, and sexually active young people (15 – 24) are most at risk. It can be difficult to know if you have chlamydia as most people do not have symptoms, and if left untreated can lead to serious long-term health consequences including infertility. The good news however, is that it is easy to diagnose and treat.
In 2010 the National Chlamydia Screening Programme (NCSP) launched a mass media campaign: “Chlamydia – Worth Talking About.” The campaign aimed to raise awareness, encourage conversations about transmission, and increase the proportion of people aged 15 – 24 years having a chlamydia test.
A previous qualitative evaluation reported the campaign was successful in raising awareness about chlamydia. Which is great news! But what we really want to know is did the campaign change behaviour. Did more people get tested for chlamydia as a result of the campaign?
This blog post looks at a further quantitative evaluation published this May (Gobin et al) which sought to find out:
- Did the mass media campaign have an impact upon test uptake?
- Did those most at risk of chlamydia (indicated by a higher proportion of positive tests) go for testing?
- A time-series of anonymised NCSP patient data over a 27 month period (April 2008 – June 2010) was retrospectively analysed. Patients were assigned to groups according to their test date (pre-campaign, campaign or post-campaign) for analysis.
- Collected data included socio-demographic information and self-reported sexual behaviour. 4% of data was appropriately excluded for the following reasons: where tests were conducted for clinical reasons, patients were contacts of known cases, from prison or military services.
- Analysis adjusted for secular and cyclical trends using binomial and logistic regression modelling.
The number of people having a chlamydia test more than doubled during the campaign phase (RR 2.23, 95% CI 2.22-2.24) compared to the pre-campaign phase. However this increase did not remain significant when the data was adjusted for secular and cyclical trends, meaning the testing increase was likely to be explained by external factors, and not attributed to the campaign.
Analysis of socio-demographic factors showed that testing of men and people of Asian ethnicity increased during the campaign phase, whereas testing in women and people of Black and Other ethnic origins fell during this phase. Testing up-take did not vary by age or socioeconomic status between phases.
The overall proportion of people testing positive increased during the campaign phase, across all socio-demographic and risk groups, even after adjustment for secular and cyclical trends.
Although the overall increase in testing uptake could not be attributed to the campaign, there was an association between the campaign and increased testing of high risk individuals (illustrated by the higher proportion of positive test results) who were previously less likely to come forward for testing (e.g. men, people of Asian ethnicity, and people with higher risk of infection (determined by self-reported sexual behaviour)).
The results of this evaluation are really interesting, but also a little disappointing as one would hope that the campaign would’ve increased uptake numbers … however this just illustrates the importance of robust methods to test different methods of health communication!
Unfortunately this study did not ascertain whether any local campaigns or interventions aimed at high-risk groups happened concurrently (this was acknowledged as a limitation), and thus we are left to assume that the mass media communication was the reason for the increased uptake of these groups.
These results mirror the findings of the previous qualitative evaluation where two-thirds of those interviewed felt that the campaign was not relevant to them, and this may explain the discrepancy of uptake across different gender and ethnicity groups in this evaluation.
This is a limitation of mass media campaigns – messages cannot be tailored to individuals, and as such, messages will not be relevant to everyone. It is therefore important to be clear about your target group and message when planning such interventions, and preferably develop messages using insight about the target group. Although the “Chlamydia – Worth Talking About”‘ campaign seems to have been effective for some groups – it is unclear why it worked for these groups (which would make it difficult to replicate the results elsewhere).
Mass media campaigns do have many advantages (e.g. they can reach many people quickly and have a low cost-per-person-reached), and are a useful tool to promote health messages. What this study illustrates is the challenge of measuring and attributing behaviour change to a campaign.
This chlamydia campaign was effective at encouraging some high-risk groups to go for screening, however more work is needed to understand why it was successful so that we can repeat what works.
Maya Gobin, Neville Verlander, Carla Maurici, Angie Bone and Anthony Nardone (2013) Do sexual health campaigns work? An outcome evaluation of a media campaign to increase chlamydia testing among young people aged 15–24 in England, BMC Public Health 2013, 13: 484 doi:10.1186/1471-2458-13-484
NHS Choices: Information on chlamydia available here
National Chlamydia Screening Programme website is available here
Video of advert used in the campaign “Chlamydia – Worth Talking About” (2010) available here