Displaying 1-9 letters out of 190 published
Street and Labour Children; Special Group for Elimination of Viral Hepatitis in Iran
We read with much interest the recently published article by Foroughi et al.  in your journal. They have demonstrated that prevalence of HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) infections among street and labour child are 4.5%, 1.7% and 2.6% in Iran, respectively and well discussed about HIV infection in this population, However, we would like to highlight some points about HBV and HCV infections among them.
First of all, we think that they may under-estimate reported prevalence rates in their study. only known street and labour children that had consent for enrollment in the study have been investigated which may cause a kind of selection bias considering socio- economic status of participants.
Treatment of HCV infection has been revolutionized and have provided an opportunity for its elimination. Patient finding is one of the major issues in the elimination program. As screening in general population is very difficult; therefore, in the first step prioritizing special groups for screening seems to be reasonable . Foroughi et al. reported HCV prevalence rate of 2.6% in Iranian street and labor children which is approximately five times higher than general population in our country . Hence, we think this group of patients needs special attention for finding of HCV-infected patients. Furthermore, Authors showed that HCV infection is six times higher in HIV-infected children compared to children without this infection. Fortunately, with new treatment strategies, HIV/HCV coinfection is not considered a special condition anymore and can be treated easily with only considering drug-drug interaction .
Finally, all participants were 10-18 years old, so they should have been vaccinated against HBV according to the national immunization program for neonates in Iran . But high reported prevalence of HBV among them and the etiology for lack of enough immunization should be more investigated.
1. Foroughi M, Moayedi-Nia S, Shoghli A, et al. Prevalence of HIV, HBV and HCV among street and labour children in Tehran, Iran. Sexually Transmitted Infections 2016:sextrans- 2016-052557
2. Hesamizadeh K, Sharafi H, Rezaee-Zavareh MS, Behnava B, Alavian SM. Next Steps Toward Eradication of Hepatitis C in the Era of Direct Acting Antivirals. Hepatitis Monthly 2016;16(4)
3. Hajarizadeh B, Razavi-Shearer D, Merat S, Alavian SM, Malekzadeh R, Razavi H. Liver Disease Burden of Hepatitis C Virus Infection in Iran and the Potential Impact of Various Treatment Strategies on the Disease Burden. Hepat Mon 2016;16(7):e37234 doi: 10.5812/hepatmon.37234[published Online First: Epub Date]|.
4. Alavian SM, Zamiri N, Gooya MM, Tehrani A, Heydari ST, Lankarani KB. Hepatitis B vaccination of adolescents: a report on the national program in Iran. Journal of public health policy 2010;31(4):478-93
Conflict of Interest:
Antiseptic mouthwash against pharyngeal Neisseria gonorrhoeae
Dear Madam, dear Sir: With interest, we read the paper of Chow et al. (1) reporting that Listerine antiseptic mouthwash can kill Neisseria gonorrhoeae in vitro and reduce the amount of gonococci on pharyngeal surfaces. There is no doubt that measures beyond antibiotic treatment of gonococcal infections detected clinically or by laboratory testing are needed to reduce the prevalence of infection and that mouthwash can diminish the gonococcal load of the oral cavity. However, we would like to point out that antiseptic mouthwash is no reliable means to prevent transmission of gonorrhea and for the following reasons may lead to a false sense of security in the persons concerned: i. Although MSM with culture-proven oral gonococcal infection were significantly less likely culture-positive after rinsing and gargling with Listerine for one minute, compared to phosphate-buffered saline (PBS), bacteria were still detected by culture in more than 50%. Daily use of Listerine mouthwash might reduce the rate of culture positive cases further, but there are no long-term data about sustained elimination of Neisseria gonorrhoeae. ii. It is well known that MSM suffering from gonorrhea are frequently infected at multiple sites. In several previous studies 20%-70% of cases with pharyngeal gonococcal infection were concomitantly positive in urogenital or anorectal specimens (2-6). Thus, even when oral gonococci will be cleared effectively by Listerine mouthwash, they can still be transmitted by genito-anal sexual contacts in a number of patients, especially when considering that the majority of anorectal gonococcal infections are asymptomatic (2,5,6). iii. Frequent use of Listerine may also damage the physiological mouth flora (oral microbiome) and thus may affect susceptibility for other infections (including HIV). Even if the reduction of pharyngeal carriage of Neisseria gonorrhoeae will be confirmed in further investigations, we do not think the use of antiseptic mouthwash should be included into the prevention strategies to control gonococcal infections. In particular, it should not be designated a "non-condom control measure", as this may erroneously be conceived as condom use is no longer essential after using antiseptic mouthwash. Furthermore, there is a concern that laboratory test to detect pharyngeal gonococcal infections and to characterize antibiotic susceptibility will be performed less frequently when antiseptic mouthwash was used. We consider it much more advisable to implement effective gonococcal screening strategies, including testing of pharyngeal, urogenital and anorectal samples, than gargling with mouthwash, which under the assumption of clearing the bacteria might adversely affect any efforts to establish effective gonococcal screening in risk populations.
References 1. Chow EP, Howden BP, Walker S et al. Antiseptic mouthwash against pharyngeal Neisseria gonorrhoeae: a randomised controlled trial and an in vitro study. Sex Transm Infect 2016 Dec 20. pii: sextrans-2016-052753. doi: 10.1136/sextrans-2016-052753. [Epub ahead of print] 2. Kent CK, Chaw JK, Wong W et al. Prevalence of rectal, urethral, and pharyngeal chlamydia and gonorrhea detected in 2 clinical settings among men who have sex with men: San Francisco, California, 2003. Clin Infect Dis 2005;41:67-74. 3. Benn PD, Rooney G, Carder C et al. Chlamydia trachomatis and Neisseria gonorrhoeae infection and the sexual behaviour of men who have sex with men. Sex Transm Infect 2007;83:106-12. 4. Ota KV, Tamari IE, Smieja M et al. Detection of Neisseria gonorrhoeae and Chlamydia trachomatis in pharyngeal and rectal specimens using the BD Probetec ET system, the Gen-Probe Aptima Combo 2 assay and culture. Sex Transm Infect 2009;85:182-6. 5. Peters RP, Verweij SP, Nijsten N, et al. Evaluation of sexual history- based screening of anatomic sites for chlamydia trachomatis and Neisseria gonorrhoeae infection in men having sex with men in routine practice. BMC Infect Dis 2011;11:203. 6. Dudareva-Vizule S, Haar K, Sailer A et al. Prevalence of pharyngeal and rectal Chlamydia trachomatis and Neisseria gonorrhoeae infections among men who have sex with men in Germany. Sex Transm Infect 2014 90:46-51
Thomas Meyer and Norbert H. Brockmeyer for the German Society of Sexually Transmitted Infections (DSTIG); Ruhr-University Bochum; St. Elisabeth-Hospital, Bleichstrasse 15, 44787 Bochum, Germany
Conflict of Interest:
Re: Oral sex practice as an essential criteria to define the safe sex behavior
We thank the contributor for his interest in our paper, and for highlighting the role of oral sex in the transmission of STI.
On a population level, public health intervention tends to focus on the encouragement of "safer" sexual practices. The British Association for Sexual Health and HIV defines safer sex as "having sex with less risk of transmission a sexually transmitted infection," and its guidance states that "The risk of catching an STI through unprotected oral sex is lower than for unprotected vaginal or anal sex, but is not zero." As such, unprotected oral sex may be considered as safer sex with respect to unprotected vaginal or anal intercourse.
Oral sex may include fellatio, cunnilingus and anilingus. While barrier methods are available for each of these exchanges, literature suggests they are used infrequently. Including oral sex in our data analyses is likely to have yielded a higher percentage of 'at risk' individuals, but without thorough exploration would have confounded our findings with participants in what are currently understood to be lower- risk activities. This may have weakened rather than strengthened our conclusions. Therefore, our data collection tool focused on the higher risk practices of unprotected vaginal and anal intercourse. No data pertaining to oral sex were collected.
We acknowledge the need for greater understanding of oral sex as a conduit for STI transmission, and realise the importance of further investigation into the role of the oropharynx as a reservoir of disease. We are grateful that the contributor has brought this to the attention of the readership, and look forward to future research in this area which falls outside the scope of our study.
 Lewis CT, de Wildt G. Sexual behaviour of backpackers who visit Koh Tao and Koh Phangan, Thailand: a cross-sectional study. Sex Transm Infect. 2016; 92:410-4.
 Clutterbuck DJ, Flowers P, Barber T; Clinical Effectiveness Group of British Association for Sexual Health and HIV (BASHH) and British HIV Association (BHIVA). UK National Guidelines on safer sex advice. Int J STD AIDS. 2012; 23:381-8.
 Stone N, Hatherall B, Ingham R, et al. Oral sex and condom use among young people in the United Kingdom. Perspect Sex Reprod Health. 2006; 38:6-12.
Conflict of Interest:
Excellent investigation of a much-needed subject
The topic of prostitution is of utmost importance to the public health. The study by Parvez, Katyal, Alper, Leibowitz, and Venters (2013) thoroughly investigates the population of female sex workers in New York City who have been arrested for prostitution. This study is seminal because it is the first one that investigates rates of sexually transmitted disease infection in female sex workers incarcerated in New York. The authors conclude that there are number of risk factors for transmission that go beyond the mere profession of the workers. The research provides data needed to make informed policy decisions relating to programs and interventions that may lower the rate of transmission of sexual diseases in the prostitution population in New York, and thus improve the overall health of individuals who come into contact with female sex workers as customers and partners. By inference the health of the entire community is better served by interventions suited to the population. This is an excellent and informative article.
Conflict of Interest:
Trimming the estimate: Unmeasured confounding in the association between pubic hair grooming and sexually transmitted infections
Osterberg et al.  assessed the association between pubic hair grooming and sexually transmitted infections (STIs) using self-reported data from a cross-sectional survey of adults aged 18 to 65 years in the United States. The primary result was that individuals who reported ever- grooming had 1.8 times the odds (odds ratio [OR]=1.8, 95% confidence limits [CL]: 1.4, 2.2) of a history of STIs compared with individuals who reported never-grooming. The authors thus concluded that pubic hair grooming is associated with a history of STIs. Nevertheless, these results may be explained by confounding, selection, misclassification, and protopathic (i.e. reverse causality) biases. We focus herein on unmeasured confounding as an alternate explanation for the observed estimates.
The authors adjusted for age and number of sexual partners, but these covariates are insufficient for adequately reducing confounding bias for the exposure-outcome association of interest. Confounding pathways include all common causes of exposure and outcome . For example, gender influences pubic hair grooming habits  and STIs , but gender was not adjusted in the analysis by Osterberg et al. . Therefore, gender is a source of unmeasured confounding and the consequences may be nontrivial.
We used data reported by Osterberg et al.  for a sensitivity analysis of unmeasured confounding using the following formula by Ding and Vanderweele  to derive an adjustment factor,
where OReu is the odds ratio for the association between gender (males as reference) and any grooming (OR=2.67), and ORud is the odds ratio for the association between gender and STIs (OR=1.43). The observed OR and corresponding CL (OR=1.8, 95% CL: 1.4, 2.2) are subsequently divided by the adjustment factor (1.23), which results in an OR=1.5 (95% CL: 1.1, 1.8) for the estimate after adjustment for gender and the original covariates (age and number of sexual partners). The adjusted estimate is attenuated from the authors' reported estimate and may be even closer to the null if other relevant covariates could be adjusted such as race/ethnicity and socioeconomic status. In addition, the authors reported that the survey used sampling probability weights, but these weights did not seem to be used in the analysis. The consequence is potential bias in point estimates and overly narrow confidence limits , which raises further questions about the authors' interpretation.
In summary, the interpretation by Osterberg et al.  may be based on biased estimates. Greater attention to unmeasured confounding and other sources of bias is warranted before attributing STIs to grooming habits.
 Osterberg EC, Gaither TW, Awad MA, Truesdale MD, Allen I, Sutcliffe S, et al. Correlation between pubic hair grooming and STIs: results from a nationally representative probability sample. Sex Transm Infect. 2016.  Greenland S, Pearl J, Robins JM. Causal diagrams for epidemiologic research. Epidemiology. 1999;10:37-48.  Butler SM, Smith NK, Collazo E, Caltabiano L, Herbenick D. Pubic hair preferences, reasons for removal, and associated genital symptoms: comparisons between men and women. J Sex Med. 2015;12:48-58.  Satterwhite CL, Torrone E, Meites E, Dunne EF, Mahajan R, Ocfemia MC, et al. Sexually transmitted infections among US women and men: prevalence and incidence estimates, 2008. Sex Transm Dis. 2013;40:187-93.  Ding P, VanderWeele TJ. Sensitivity Analysis Without Assumptions. Epidemiology. 2016;27:368-77.  Kreuter F, Valliant R. A survey on survey statistics: What is done and can be done in Stata. Stata Journal. 2007;7:1.
Conflict of Interest:
Oral sex practice as an essential criteria to define the safe sex behavior
Modifying sexual behavior remains the primary goal of preventing the transmission of HIV/STIs among populations. However, with the various borderlines of "safe sex" definition, people sometimes get confused to describe how to practice low-risk sex activities. In general, safe sex is defined as sexual activities in which avoiding any bodily fluid exchanges (sperm, vaginal fluid, blood, and saliva), with the aim of preventing HIV/STIs transmission (1). According to this definition, we may correlate safe sex behaviors with the use of condoms during sexual intercourse from anal, vaginal, and oral sex. In the study, analysis of measuring safe sex acts with consistent condom use was devoted to the anal and vaginal sex, yet it excluded oral sex (2). In fact, oral sex plays a significant role in the transmission of important STIs, such as syphilis, herpes, warts, and gonorrhea (3). One case belongs to pharyngeal gonorrhea which is widely spread through intense oral sex practices (4). Pharyngeal gonorrhea now has been raising in incidence especially in developed countries (5) as higher oral sex practices than coital sex (6). Hence, oral sex is closely associated with further gonorrhea transmission (7), and more importantly, it is highly likely to induce antimicrobial resistance (super gonorrhea) (8, 9). Considering the significant role of oral sex, several study included oral sex variable to define "consistent condom use" criteria (10, 11). In my opinion, applying the variable of oral sex in the data analysis may influence the final results and conclusions in this study. Some studies revealed inconsistent condom use occurred more frequent during oral sex (12, 13), due to the erroneous perceptions towards the role of oral sex in spreading STIs (14). This research would give benefits in providing evidence on traveler's sexual behaviors and provide fundamental inputs to develop health promotion strategies for this population. More specifically, the result of the study could help Thailand government in evaluating the 100% condom program for sex workers (15), by identifying the rate of condom use among travelers who had sex with local sex workers.
Reference 1.Safe sex [Def. 1]. (n.d.). Merriam-Webster Online. In Merriam-Webster. Retrieved November 16, 2016, from www.merriam- webster.com/dictionary/safe%20sex 2.Lewis, C. T., and G. de Wildt. 'Sexual Behaviour of Backpackers Who Visit Koh Tao and Koh Phangan, Thailand: A Cross-Sectional Study', Sexually Transmitted Infections, vol. 92/no. 6, (2016), pp. 410-414. 3.Kumar, Tarun, Gagan Puri, Konidena Aravinda, et al. 'Oral Sex and Oral Health: An Enigma in itself', Indian Journal of Sexually Transmitted Diseases, vol. 36/no. 2, (2015), pp. 129-132. 4.Wiesner, Paul J., Evelyn Tronca, Paul Bonin, et al. 'Clinical Spectrum of Pharyngeal Gonococcal Infection', The New England Journal of Medicine, vol. 288/no. 4, (1973), pp. 181-185. 5.Morris, Sheldon R., Jeffrey D. Klausner, Susan P. Buchbinder, et al. 'Prevalence and Incidence of Pharyngeal Gonorrhea in a Longitudinal Sample of Men Who have Sex with Men: The EXPLORE Study', Clinical Infectious Diseases, vol. 43/no. 10, (2006), pp. 1284-1289. 6.Halpern-Felsher, Bonnie L., Jodi L. Cornell, Rhonda Y. Kropp, et al. 'Oral Versus Vaginal Sex among Adolescents: Perceptions, Attitudes, and Behavior', Pediatrics, vol. 115/no. 4, (2005), pp. 845-851 7.Weinstock, Hillard, and Kimberly A. Workowski. 'Pharyngeal Gonorrhea: An Important Reservoir of Infection?', Clinical Infectious Diseases, vol. 49/no. 12, (2009), pp. 1798-1800. 8.Deguchi, Takashi, Mitsuru Yasuda, and Shin Ito. 'Management of Pharyngeal Gonorrhea is Crucial to Prevent the Emergence and Spread of Antibiotic-Resistant Neisseria Gonorrhoeae', Antimicrobial Agents and Chemotherapy, vol. 56/no. 7, (2012), pp. 4039-4040. 9.Gratrix, Jennifer, Joshua Bergman, Cari Egan, et al. 'Retrospective Review of Pharyngeal Gonorrhea Treatment Failures in Alberta, Canada', Sexually Transmitted Diseases, vol. 40/no. 11, (2013), pp. 877-879 10.Crosby, Richard A., Cynthia A. Graham, William L. Yarber, et al. 'Measures of Attitudes Toward and Communication about Condom use: Their Relationships with Sexual Risk Behavior among Young Black Men Who have Sex with Men', Sexually Transmitted Diseases, vol. 43/no. 2, (2016), pp. 94- 98. 11.Fridlund, Veronika, Karin Stenqvist, Monica K. Nordvik, et al. 'Condom use: The Discrepancy between Practice and Behavioral Expectations', Scandinavian Journal of Public Health, vol. 42/no. 8, (2014), pp. 759-765. 12.Stone, Nicole, Bethan Hatherall, Roger Ingham, et al. 'Oral Sex and Condom use among Young People in the United Kingdom', Perspectives on Sexual and Reproductive Health, vol. 38/no. 1, (2006), pp. 6-12. 13.Noar, Seth M., Elizabeth Webb, Stephanie Van Stee, et al. 'Sexual Partnerships, Risk Behaviors, and Condom use among Low-Income Heterosexual African Americans: A Qualitative Study', Archives of Sexual Behavior, vol. 41/no. 4, (2012), pp. 959-970. 14.Minichiello, V., R. Mari?o, and J. Browne. 'Knowledge, Risk Perceptions and Condom Usage in Male Sex Workers from Three Australian Cities', AIDS Care, vol. 13/no. 3, (2001), pp. 387-402. 15.Rojanapithayakorn, W., and R. Hanenberg. 'The 100% Condom Program in Thailand', AIDS (London, England), vol. 10/no. 1, (1996), pp. 1-8.
Lukman Ade Chandra Postgraduate student of Master of Medicine/Master of Philosophy (HIV, STI, and Sexual Health), University of Sydney, Australia 38 Cleveland St, Chippendale, Sydney, NSW, Australia 2008 email: firstname.lastname@example.orgemail@example.com
Conflict of Interest:
Just a few thoughts
The study by Girometti et al(1) on the incidence of human immunodeficiency virus(HIV) in men that have sex with men(MSM) with early syphilis illustrated the role syphilis plays in HIV transmission. However, although syphilis is a risk factor for HIV infection, chlamydia and gonorrhea are also risk factors for the transmission of HIV(2). Unless it is clearly stated that the participants that acquired HIV during the study only had 'early syphilis', any association between HIV seroconversion and the stated predictor will be confounded because the other STIs are also known causes of increased risk for HIV infection(2). Also, behavior such as the use of condom plays a huge role in HIV acquisition. Additionally, the practice of oral sex may have different risk of HIV transmission compared to anal sex, although this risk may be modified by the presence of oral syphilitic lesions(3). Therefore, an individual that have syphilis and practices oral sex or uses condom may have a lesser risk of acquiring HIV than an individual that does not.
Of the 206 MSM that were diagnosed with early syphilis, 191 were treated, and 26 had reinfection. What is the fate of the 15 cases of syphilis that weren't treated? How many of these acquired HIV? What is 'early syphilis': Is it early Primary(Chancre), early Secondary or Early Latent syphilis? Lastly, although the reduction of HIV incidence by Pre- Exposure Prophylaxis(PreP) in MSM is found to be 86%, and giving PreP to MSM who have other STIs is ideal, using syphilis or any other STI alone as a marker for PreP can cause misclassification for PreP use. For instance, will you prefer to give PreP to an MCM with syphilis from an area with high syphilis prevalence over someone from a similar area of prevalence but doesn't have syphilis and consistently refuses to use condom compared to the former person? Thus, the result of this study may only be useful for a specific population, most likely where the study was done. With all the above, the conclusion by the author that early syphilis increases the incidence of HIV in MCM by 8.3 times may not be practical.
1. Girometti N, Gutierrez A, Nwokolo N, McOwan A, Whitlock G. High HIV incidence in men who have sex with men following an early syphilis diagnosis: is there room for pre-exposure prophylaxis as a prevention strategy? Sex Transm Infect. 2016 Oct 19;sextrans-2016-052865. 2. Hoenigl M, Green N, Mehta SR, Little SJ. Risk Factors for Acute and Early HIV Infection Among Men Who Have Sex With Men (MSM) in San Diego, 2008 to 2014. Medicine (Baltimore) [Internet]. 2015 Jul 31 [cited 2016 Oct 27];94(30). Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554110/ 3. Transmission of Primary and Secondary Syphilis by Oral Sex --- Chicago, Illinois, 1998--2002 [Internet]. [cited 2016 Oct 27]. Available from: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5341a2.htm
Conflict of Interest:
In support of a structured approach to service design and evaluation in chlamydia screening
We read with interest the recent article by Chandrasekaran et al, which analysed national surveillance data on chlamydia testing and diagnoses among young adults in England in 2012. The paper raises a number of important points of relevance for the National Chlamydia Screening Programme in England.
Firstly, the authors' findings further support the known association between deprivation and chlamydia infection[2;3]. Although Chandrasekaran et al present an ecological study, this relationship has also been demonstrated in individual level analyses and emphasises the importance of chlamydia screening delivery in socioeconomically deprived areas. For local authorities thinking about the implications of these findings for their own populations, it is also worth noting that within a single local authority area, levels of deprivation will vary. Therefore decisions about focussing of resources need to be considered at several levels.
The observation that areas with a lower proportion of tests carried out in GUM clinics were less likely to achieve a detection rate of 2,300/100,000 population is also an important one. Chlamydia infections are not restricted to young adults with higher risk sexual behaviours, such as multiple sexual partners, nor to those who attend GUM clinics[2;3]. Testing in non-GUM clinic settings such as sexual and reproductive health services, primary care and via the internet is therefore an essential component of comprehensive chlamydia control.
Along with differences in infection risk in different populations, the other driver of variation in detection rates is testing coverage, as the authors themselves point out. Although the relationship between coverage and detection rates was not explored explicitly in this paper, we note that coverage was higher in more deprived local authorities. In national surveillance data from 2015, local authorities with higher coverage tended to have higher detection rates. This suggests that in 2012, chlamydia screening activity was, to some extent, already focussed in areas at greatest need. However, more could be done to increase detection rates as we know that infections go undiagnosed3, with the consequent potential impact on reproductive health. The old adage of 'seek and ye shall find' holds true to a large extent with chlamydia testing among young adults; the decision for local authorities is how best to use the available resources to maximise the benefit of every test.
To that end, we also welcome the authors' recommendation that local authorities be encouraged to use their data to inform service planning and evaluation. As the authors conclude, this understanding of the data should not be limited to a narrow focus on the detection rate indicator alone. Diagnosis is only one step of the process by which chlamydia screening can identify and treat infections. Understanding of the population(s) at risk, rates of testing, diagnosis, treatment, partner notification and re- testing are all needed to ensure a quality service. In recognition of this, the NCSP is already working with local authorities and service providers to use both nationally- and locally-collated data relating to the whole of the chlamydia care pathway to inform service improvement activity. We believe this structured approach to service design and evaluation will ensure that commissioners are best able to allocate limited resources to achieve the maximum benefit for the population.
 Chandrasekaran L, Davies B, Eaton JW, Ward H. Chlamydia diagnosis rate in England in 2012: an ecological study of local authorities. Sex Transm Infect 2016.
 Sonnenberg P, Clifton S, Beddows S, Field N, Soldan K, Tanton C et al. Prevalence, risk factors, and uptake of interventions for sexually transmitted infections in Britain: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal). Lancet 2013; 382(9907):1795- 1806.
 Woodhall SC, Soldan K, Sonnenberg P, Mercer CH, Clifton S, Saunders P et al. Is chlamydia screening reaching young adults at risk of infection? Findings from the third National Survey of Sexual attitudes and Lifestyles (Natsal-3). Sexually Tranmitted Infections 2016; 92(3):218-227.
 Public Health England. Sexually transmitted infections and chlamydia screening in England, 2015. Health Protection Report 2016; 10(22).
 Price MJ, Ades AE, Soldan K, Welton NJ, Macleod J, Simms I et al. The natural history of Chlamydia trachomatis infection in women: a multi parameter evidence synthesis. Health Technology Assessment 2016; 20(22).
 Public Health England. NCSP: Care pathway. 2016. Available at: https://www.gov.uk/government/publications/ncsp-chlamydia-care-pathway Accessed 2 Sep 2016
Conflict of Interest:
All authors are employed by Public Health England and contribute to the implementation, monitoring and/or evaluation of the National Chlamydia Screening Programme in England.
Re: Retesting Chlamydia trachomatis in a GUM clinic in London, UK
Thank you very much for carefully reading our article and for your positive feedback. We have read your E-letter with great interest. We are pleased that our publication contributed to adjustment of your policy concerning retesting. Implementing a text message reminder and lengthening the follow up period to 3 months is likely to elevate the return rate and positivity rate. According to our research, you may even consider lengthening the follow up period to 6 months to yield even more chlamydia reinfections.
In your letter you show that you already achieve a relatively high return rate of 26.8% without sending a text message reminder. Also, in research from Burton et al, 2014, the return rate was high with 35% without sending a text message reminder. These are much higher return rates than in our control group (9.2%). In your E-letter (Ahmed et al. STI, 2016), you question whether patients in the Netherlands are advised to do a repeat test. We do have an informal guideline concerning this advice, though it is not certain that every clinic in our study group gave this advice. Therefore we cannot state that this retest-advice is consistently given, and that could have (in part) caused our relatively low return-rates in the control group. Also, you state in the E-letter that sexual health appointments in your service are available by booking in advance or on the day. It is unclear to me whether this means that an appointment for retest is already made after initial consultation or that patients who want to do a retest can come at any day. In our study, booking in advance was not done. In our STI clinics, the usual waiting time for non-emergency sexual health consultations is 2-3 weeks. This could be an additional factor in the difference between our return rate and the return rate of the UK research described.
In the Netherlands, the sexual health clinics are exploring and implementing cost-effective strategies to lower the threshold for (re- )testing on STI. As an example of how to make retesting more (cost-) effective, we like to refer to a Dutch article by Gotz, et al , where the retest participation was higher in the patient-group that received a testkit at their home address (46%, 50/109), compared to the group asked to visit the STI clinic for retesting without an appointment (23%, 25/107). Home-based testkits can be a good method to increase the re- attendance rate. Though some STI-clinics in the Netherlands implement this strategy for low-risk patients, it hasn't yet been implemented for the purpose of a retest. This might, however, be an interesting cost-effective way to identify chlamydia reinfections.
 G?tz HM, Wolfers MEG, Luijendijk A, van den Broek IVG. Retesting for genital Chlamydia trachomatis among visitors of a sexually transmitted infections clinic: randomized intervention trial of home- versus clinic- based recall. BMC Infectious Diseases 2013, 13:239
Conflict of Interest: