Rapid Responses to:

CLINICAL REVIEW: Richard J C Gilson and Adrian Mindel Recent advances: Sexually transmitted infections BMJ 2001; 322: 1160-1164 [Full text]

Rapid Responses: Submit a response to this article

Rapid Responses published:

Genito-urinary Chlamydial infection: how to diagnose?

Dhinagar Subramanian   (30 May 2001)

sexually transmitted infections

Sonja Castermans, Jef Verheyen, Pierre van Damme   (12 June 2001)

The News Isn't All Bad

Barry E Kenneally   (19 June 2001)

Genito-urinary Chlamydial infection: how to diagnose? 30 May 2001
Dhinagar Subramanian, Specialist Registrar in Microbiology Leeds General infirmary Send response to journal: Re: Genito-urinary Chlamydial infection: how to diagnose?	Editor,-We read with interest the article by Gilson and Mindel1 on recent advances in the management of sexually transmitted infections, which emphasised some important diagnostic issues. As the authors state, many studies have shown that DNA amplification tests are now the gold standard tests for the diagnosis of genital Chlamydia trachomatis. However, we are concerned with the unreferenced statement that a ‘vaginal swab is a better alternative’ for the detection of genital chlamydial infection. We could find two studies which have examined the utility of vaginal swabs, collected either by health care personnel or patients themselves.2,3 Both found high sensitivity for vaginal swabs, but this was matched by the sensitivity of sampling both urine (as a surrogate for the urethra) and the cervix. Indeed, in some cases of genital chlamydial infections (cervical swab positive) vaginal swabs were negative.2 In women, the sensitivity of C. trachomatis PCR testing is increased by approximately 12% if both cervical swab and urine specimens are examined as opposed to urine alone.4 However, this approach is expensive, particularly considering the relatively high cost of PCR tests versus enzyme immunoassays. We found that combining a cervical swab with a urine specimen in the clinic setting is acceptable for PCR testing for genital C. trachomatis infection,5 and has the potential to increase further the cost-effectiveness of DNA based screening for C. trachomatis genital infection. Thus, this approach has the advantage of sampling both the main sites of genito-urinary chlamydial infection and being more cost- effective. Also, the well known problem of DNA amplification inhibition by endogenous substances present in urine, and more commonly in cervical secretions, is not increased by combining the two sample types.5 Mark H Wilcox Consultant Microbiologist, Leeds General Infirmary, Leeds. Dhinagar Subramanian Specialist Registrar, Department of Microbiology, Leeds General Infirmary, Leeds References 1. Gilson RJC, Mindel A. Recent advances: Sexually transmitted infections. BMJ 2001; 322: 1160-1164. 2. Domeika M, Bassiri M, Butrimiene I, Venalis A, Ranceva J, Vasjanova V. Evaluation of vaginal introital sampling as an alternative approach for the detection of genital Chlamydia trachomatis infection in women. Acta Obstet Gynecol Scand. 1999; 78(2):131-6. 3. Wiesenfeld HC, Heine RP, Rideout A, Macio I, DiBiasi F, Sweet RL.The vaginal introitus: a novel site for Chlamydia trachomatis testing in women. Am J Obstet Gynecol. 1996; 174(5):1542-6. 4. Quinn TC, Welsh L, Lentz A, Crotchfelt K, Zenilman J, Newhall J et al. Diagnosis by AMPLICOR PCR of Chlamydia trachomatis infection in urine samples from women and men attending sexually transmitted disease clinics. J Clin Microbiol 1996; 34: 1401-6. 5. Wilcox MH, Reynolds MT, Hoy CM, Brayson J.Combined cervical swab and urine specimens for PCR diagnosis of genital Chlamydia trachomatis infection.Sex Transm Infect. 2000; 76(3):177-8.
sexually transmitted infections 12 June 2001
Sonja Castermans, epidemiology and social medicine university of Antwerp, Jef Verheyen, Pierre van Damme Send response to journal: Re: sexually transmitted infections	Dear Editor, In their article Gilson and Mindel report on the increasing burden of sexually transmitted infections (STI) in industrialised countries, in particular in young people (1). New opportunities for controlling and early detection of STIs are discussed. Although all very promising, the implementation remains often problematic. Similarly, this is also valid for the future STI vaccines. Vaccination remains the most promising intervention for communicable disease control. Vaccines against herpes simplex and human papillomavirus are under development, and safe and effective hepatitis B vaccines are now 20 years on the market. All these STI vaccines could offer important individual as well as collective health gains; there is overwhelming evidence that a suitable hepatitis B vaccination programme would confer protection on over 90% of the vulnerable individuals. The hepatitis B vaccine story illustrates however, as alluded to in Catchpole’s Editorial, that the availability of efficacious vaccines is not enough to ensure efficient adoption of these vaccines in the fight against STIs (2). Recent history has shown that the implementation of a well-considered hepatitis B vaccination programme can be problematic and not evident at all (3). Three lessons can be learnt from this story: -opportunistic vaccination of those in the age group at highest risk (i.e. adolescents) has been undertaken only in a minority of industrialised countries, even sometimes at very low vaccination coverage (3). -vaccination of risk groups hasn’t been very successful up to now, and is very demanding in terms of manpower and programme costs (4,5). -as long as decision makers and the public don’t accept the universal (targeting a whole age cohort) introduction of an STI vaccine, especially its administration in childhood, control of STI through universal vaccination will remain difficult. The time is yet mature for drawing lessons for the future, i.e. learn from the current experience with hepatitis B vaccination programmes, evaluate and, if needed, strengthen and improve these vaccination programmes and prepare the field as well as the public for the venue of future STI vaccines. If we are not able to use the currently available hepatitis B vaccines efficiently to protect our future generations of adolescents in industrialised countries, what is the rationale for developing new STI vaccines, except conferring protection to a few individuals. We should therefore, in parallel with the development of new STI vaccines, start thinking today about how to deliver hepatitis B vaccines to those who need it most; this will open the door to future STI vaccines. 1. Gilson R, Mindel A. Recent advances: sexually transmitted infections. BMJ 2001; 322: 1160-4. 2. Catchpole M. Sexually transmitted infections: control strategies. BMJ 2001; 322: 1135-6 (editorial). 3. Van Damme P. Hepatitis B vaccination programmes in Europe: an update. Vaccine 2001; 19: 2375-2379. 4. Bhatti N, Gilson RJC, Beecham M, Williams P, Matthews MP, Tedder RS, Weller IVD. Failure to deliver hepatitis B vaccine: confessions from a genitourinary medicine clinic. BMJ 1991; 303: 97-101. 5. Hoebe CJPA, Ruijs WLM, Schutten M, Waldhober Q, van Steenbergen JE. Results of the first year of a hepatitis B pilot vaccination program for hard drug users, homosexual men and promiscuous heterosexuals in the Netherlands. Antiviral Therapy 2000; 5 (suppl. 1): 20-21. Castermans S, medical student, research training programme Verheyen J, medical student, research training programme Van Damme P, head, Centre for the Evaluation of Vaccination Dept. Epidemiology and Social Medicine, University of Antwerp, Belgium
The News Isn't All Bad 19 June 2001
Barry E Kenneally, University of Pennsylvania Student Health Service Send response to journal: Re: The News Isn't All Bad	Gilson and Mindel provide an excellent review of sexually transmitted infections (STI). The recent increase in the reported numbers of STI is alarming. Some reports indicate that sexually risk taking has increased now that effective HIV drugs are available1. However, not all of the news is bad. One important reason for the increased number of cases is that better tests are being used. The sensitivity of DNA amplification tests approaches 100 percent. In one study, switching to these newer tests resulted in an increased positivity of 46 percent2. Newer urine based testing may help broaden screening to include men. Chlamydia screening programs are another reassuring reason to expect more reported cases. The U.K. broadened its screening recommendations in 1998. The number of U.S. states requiring reporting of Chlamydia cases increased steadily between 1987 and 1996. Implementation of screening is still inadequate3, but as more physicians begin screening, we can expect some rise in the number of reported cases. Many populations being screened for Chlamydia are actually experiencing lower rates of infection4. University health clinics in the U.S. have seen a steady decrease in Chlamydia prevalence from over 4 percent in the mid 1990's to less than 2 percent presently5. Despite the increasing numbers of reported cases, STI screening is effective in preventing STI and pelvic inflammatory disease6. 1 Aral S, Holmes KK. Social and behavioral determinants of the epidemiology of STDs: industrialized and developing countries. In: Holmes KK, ed. Sexually transmitted diseases. 3rd ed. New York: McGraw-Hill, 1999:39-76. 2 Dicker LW, Mosure DJ, Levine WC, Black CM, Berman SM. Impact of switching laboratory tests on reported trends in Chlamydia trachomatis infections. Am J Epidemiol 2000;151:430-5. 3 Torkko KC, Gershman K, Crane LA, Hamman R, Baron A. Testing for Chlamydia and sexual history taking in adolescent females: results from a statewide survey of Colorado primary care providers. Pediatrics 2000;106(3):e32. 4 Division of STD Prevention. Sexually Transmitted Disease Surveillance, 1999. U.S. Department of Health and Human Services, Atlanta: Centers for Disease Control and Prevention (CDC), September 2000. 5 American College Health Association. Survey of Sexually Transmitted Infections. Annual Meeting. Toronto, Canada. June 2000. 6 Scholes D, Stergachis A, Heidrich FE, Andrilla H, Holmes KK, Stamm WE. Prevention of pelvic inflammatory disease by screening for cervical Chlamydia infection. NEJM 1996;334:1326-6.