Title: Swab-yourself trial with economic monitoring and testing for infections collectively (SYSTEMATIC): A study comparing clinician-taken versus self-taken rectal and pharyngeal samples, and separate versus pooled specimens, from each individual
Funder: Department of Health (England)

Abstract: Background Current screening for chlamydia (CT) and gonorrhoea (GC) in the community outside clinical settings (not in a hospital, clinic or surgery) is with self-taken urogenital samples only. Yet these infections are also commonly found in extra-genital (pharynx and rectum) sites so are not detected by these samples. In men who have sex with men (MSM) the majority of infections are extra-genital and so are missed by current screening. The use of self-taken swabs from extra-genital sites would allow full screening to be introduced into community settings, thus identifying all infections and contributing to control. Tests for GC and CT using nucleic acid amplification tests (NAATs) are easy to use in all settings as they do not require incubation, but they are expensive. If rectal and pharyngeal specimens are processed in addition to the routine urogenital area, the diagnostic cost is trebled, making it too expensive for most NHS services. If all samples taken from a person (urogenital tract, rectum, pharynx) could be pooled and analysed together, the cost of the diagnostic analysis would be the same cost as current screening but without missing any infections (assuming the same sensitivity and specificity of the tests). Aims and objectives Improve detection of GC and CT by: Comparing sensitivity and specificity of pooled self-taken samples with individually analysed clinician-taken samples Comparing sensitivity of individually analysed self-taken swabs of rectum and pharynx with individually analysed clinician-taken swabs Comparing sensitivity and specificity of pooled self-taken samples with self-taken samples analysed individually Calculating and comparing the cost-effectiveness and cost per infection found by self-taken swabs versus clinician-taken swabs in pooled versus individually analysed samples. Plan of Investigation Women and MSM, attending for sexual health tests, will be recruited. Each will have three sets of samples taken. In women these will be: clinician-taken rectal and pharyngeal swabs to be processed separately; self taken rectal and pharyngeal swabs plus VVS to be processed separately; self-taken rectal, pharyngeal and VVS samples to be processed as a pooled specimen. In MSM these will be: clinician-taken rectal and pharyngeal swabs to be processed separately; self taken rectal and pharyngeal swabs plus FPU to be processed separately; self-taken rectal, pharyngeal and FPU samples to be processed as a pooled specimen. The order the samples are taken in will be randomised. The sensitivity of self-taken rectal and pharyngeal swabs tested for GC and CT by NAATs will be compared with clinician-taken rectal and pharyngeal swabs. The sensitivity and specificity of the pooled rectal, pharygeal and urogenital samples (FPU in men, VVS in women) tested for GC and CT by NAATs will be compared with (a) individually analysed self-taken samples, and (b) individually analysed clinician-taken samples. The sensitivity and specificity will be presented with 95% confidence intervals, and any differences will be assessed using Chi-squared tests or Fisher’s Exact Test as appropriate. The number of additional infections identified or missed will also be calculated. Summary of Benefits If self-taken pooled-samples detect more people with infections and do not reduce the sensitivity and specificity of the FPU/VVS, it would mean extra-genital swabs could be incorporated into community screening, and the cost of their analysis would be the same as the current urogenital screening. This will prevent false reassurance of the individual, and the public health consequences, of negative urogenital community screening where extra-genital infections have been missed, yet at the same cost as current screening. There will be benefits to individuals and public health in that more infections will be diagnosed resulting in treatment and reduction in complications, and partner notification thus reducing onward transmission and the risk of HIV acquisition.


Research activity codes: 4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: INFECTION