ABSTRACT
BACKGROUND: A national multimedia campaign was launched in January 2010, to increase the proportion of young people tested for chlamydia. This study aimed to evaluate the impact of the campaign on the coverage and positivity within the National Chlamydia Screening Programme (NSCP) in England. METHOD: An interrupted time series of anonymised NCSP testing reports for England for a 27 month period (1st April 2008 to 30th June 2010) was analysed. Reports were assigned to a pre-campaign, campaign and post campaign phase according to the test date. Exclusion criteria included tests for clinical reasons, contacts of known cases, and tests returned from prisons or military services.Negative binomial and logistic regression modelling was used to provide an estimate for the change in coverage and positivity, during, and after the campaign and estimates were adjusted for secular and cyclical trends. RESULTS: Adjusting for cyclical and secular trends, there was no change in the overall testing coverage either during (RR: 0.91; 95% CI: 0.72-1.14) or after (RR: 0.88; 95%CI: 0.69-1.11) the campaign. The coverage varied amongst different socio-demographic groups, testing of men increased during the campaign phase while testing of people of black and other ethnic groups fell in this phase. The positivity rate was increased during the campaign (OR: 1.18; 95% CI 1.13-1.23) and further increased in the post-campaign phase (OR: 1.40; 95% CI 1.30-1.51). The proportion of chlamydia infections detected increased for all socio-demographic and self-reported sexual behaviour groups both during and after the campaign. CONCLUSION: The uptake of chlamydia testing rose during the campaign; however, this apparent increase was not maintained once overall trends in testing were taken into account. Nonetheless, once secular and cyclical trends were controlled for, the campaign was associated with an increased positivity linked to increased testing of high risk individuals groups in the target population who were previously less likely to come forward for testing. However, our study indicated that there may have been a disparity in the impact of the campaign on different population groups. The content and delivery of ongoing and future information campaigns aimed at increasing chlamydia screening should be carefully developed so that they are relevant to all sections of the target population.
