Format

Send to

Choose Destination
Epidemics. 2010 Sep;2(3):123-131. doi: 10.1016/j.epidem.2010.04.002. Epub 2010 Apr 24.

Transmission dynamics of Chlamydia trachomatis affect the impact of screening programmes.

Author information

1
Institute of Social and Preventive Medicine (ISPM), University of Bern, 3012 Bern, Switzerland. Electronic address: christian.althaus@alumni.ethz.ch.
2
Institute of Social and Preventive Medicine (ISPM), University of Bern, 3012 Bern, Switzerland.
3
Department of Statistics and Applied Probability, National University of Singapore, Singapore 117546, Singapore.

Abstract

To assess the impact of screening programmes in reducing the prevalence of Chlamydia trachomatis, mathematical and computational models are used as a guideline for decision support. Unfortunately, large uncertainties exist about the parameters that determine the transmission dynamics of C. trachomatis. Here, we use a SEIRS (susceptible-exposed-infected-recovered-susceptible) model to critically analyze the turnover of C. trachomatis in a population and the impact of a screening programme. We perform a sensitivity analysis on the most important steps during an infection with C. trachomatis. Varying the fraction of the infections becoming symptomatic as well as the duration of the symptomatic period within the range of previously used parameter estimates has little effect on the transmission dynamics. However, uncertainties in the duration of temporary immunity and the asymptomatic period can result in large differences in the predicted impact of a screening programme. We therefore analyze previously published data on the persistence of asymptomatic C. trachomatis infection in women and estimate the mean duration of the asymptomatic period to be longer than anticipated so far, namely 433 days (95% CI: 420-447 days). Our study shows that a longer duration of the asymptomatic period results in a more pronounced impact of a screening programme. However, due to the slower turnover of the infection, a substantial reduction in prevalence can only be achieved after screening for several years or decades.

PMID:
21352783
DOI:
10.1016/j.epidem.2010.04.002
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center