Antibody Testing in Estimating Past Exposure to Chlamydia trachomatis in the Netherlands Chlamydia Cohort Study.

Van Willige Van Willige,Hoebe Hoebe,Dukers-Muijrers Dukers-Muijrers,Land Land,Morré Morré,Götz Götz,Van Benthem Van Benthem,Hoenderboom Hoenderboom,Van Bergen Van Bergen,Pleijster Pleijster

doi:10.3390/microorganisms7100442

Abstract

The asymptomatic course of Chlamydia trachomatis (CT) infections can result in underestimated CT lifetime prevalence. Antibody testing might improve this estimate. We assessed CT antibody positivity and predictive factors thereof in the Netherlands Chlamydia Cohort Study. Women who had ≥1 CT Nucleic Acid Amplification Test (NAAT) in the study (2008–2011) and who provided self-reported information on NAATs were tested for CT major outer membrane protein specific IgG in serum (2016). CT antibody positivity was assessed and predictive factors were identified using multivariable logistic regressions, separately for CT-positive women (≥1 positive NAAT or ≥1 self-reported positive CT test) and CT-negative women (negative by study NAAT and self-report). Of the 3,613 women studied, 833 (23.1%) were CT -positive. Among the CT-negative women, 208 (7.5%, 95% CI 6.5–8.5) tested positive for CT antibodies. This increased CT lifetime prevalence with 5.8% (95% CI 5.0–6.5). Among women with a CT-positive history, 338 (40.6%, 95% CI 38.5–44.1) tested positive. Predictive factors for antibody positivity related to lower social economic status, sexual risk behavior, multiple infections, higher body mass index, and non-smoking. CT antibody testing significantly increased the lifetime prevalence. Combining NAAT outcomes, self-reported positive tests, and antibody testing reduced misclassification in CT prevalence estimates.

Highlights

Disease monitoring and proper evaluation of Chlamydia trachomatis (CT) control efforts are important and require accurate estimates of current and lifetime CT prevalence [1]
Among women who previously tested positive for CT by Nucleic Acid Amplification Test (NAAT), 40% tested positive for the CT IgG antibodies
CT IgG antibody testing identified 208 unnoticed CT infections among 2,780 women; infections that otherwise would have been missed. In this population of women with a mean age of 31 (SD 4), lifetime CT prevalence increased by six percent from 23% (i.e., Chlamydia Screening Implementation (CSI)–NAAT positive or self-reported positive tests) to 29%, including CT antibody testing

Summary

Introduction

Disease monitoring and proper evaluation of Chlamydia trachomatis (CT) control efforts are important and require accurate estimates of current and lifetime CT prevalence [1] This is, challenging given the asymptomatic nature of the CT infection. Current prevalence estimates and our understanding of CT related complications are primarily based on studies that measure current (vaginal) infections by using nucleic acid amplification tests (NAATs) [2,3]. These tests have a high sensitivity to detect CT [4]. Estimating the proportion of infected women that later experiences CT related complications is difficult [8,9]

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