Sexually transmitted infections (STIs) - All you need to know

Key facts

• More than 1 million sexually transmitted infections (STIs) are acquired every day worldwide.
• Each year, there are an estimated 357 million new infections with 1 of 4 STIs: chlamydia, gonorrhea, syphilis, and trichomoniasis.
• More than 500 million people are estimated to have genital infection with herpes simplex virus (HSV).
• More than 290 million women have human papillomavirus (HPV) infection (1).
• The majority of STIs have no symptoms or only mild symptoms that may not be recognized as an STI.
• STIs such as HSV type 2 and syphilis can increase the risk of HIV acquisition.
• 988 000 pregnant women were infected with syphilis in 2016, resulting in over 200 000 stillbirths and newborn deaths.
• In some cases, STIs can have serious reproductive health consequences beyond the immediate impact of the infection itself (e.g., infertility or mother-to-child transmission)
• Drug resistance, especially for gonorrhea, is a major threat to reducing the impact of STIs worldwide.

Scope of the problem

STIs have a profound impact on sexual and reproductive health worldwide.

More than 1 million STIs are acquired every day. Each year, there are estimated 357 million new infections with 1 of 4 STIs: chlamydia (131 million), gonorrhea (78 million), syphilis (5.6 million) and trichomoniasis (143 million). More than 500 million people are living with genital HSV (herpes) infection. At any point in time, more than 290 million women have an HPV infection, one of the most common STIs.

STIs can have serious consequences beyond the immediate impact of the infection itself.

• STIs like herpes and syphilis can increase the risk of HIV acquisition three-fold or more.
• Mother-to-child transmission of STIs can result in stillbirth, neonatal death, low-birth-weight and prematurity, sepsis, pneumonia, neonatal conjunctivitis, and congenital deformities. Over 900 000 pregnant women were infected with syphilis resulting in approximately 350 000 adverse birth outcomes including stillbirth in 2012 (2).
• HPV infection causes 528 000 cases of cervical cancer and 266 000 cervical cancer deaths each year.
• STIs such as gonorrhea and chlamydia are major causes of pelvic inflammatory disease (PID) and infertility in women.

Prevention of STIs

Counseling and behavioral approaches

Counseling and behavioral interventions offer primary prevention against STIs (including HIV), as well as against unintended pregnancies. These include:

• comprehensive sexuality education, STI and HIV pre- and post-test counseling;
• safer sex/risk-reduction counseling, condom promotion;
• interventions targeted at key populations, such as sex workers, men who have sex with men and people who inject drugs; and
• education and counseling tailored to the needs of adolescents.

In addition, counseling can improve people’s ability to recognize the symptoms of STIs and increase the likelihood they will seek care or encourage a sexual partner to do so. Unfortunately, lack of public awareness, lack of training of health workers, and long-standing, widespread stigma around STIs remain barriers to greater and more effective use of these interventions.

Barrier methods
When used correctly and consistently, condoms offer one of the most effective methods of protection against STIs, including HIV. Female condoms are effective and safe but are not used as widely by national programs as male condoms.

Diagnosis of STIs

Accurate diagnostic tests for STIs are widely used in high-income countries. These are especially useful for the diagnosis of asymptomatic infections. However, in low- and middle-income countries, diagnostic tests are largely unavailable. Where testing is available, it is often expensive and geographically inaccessible; and patients often need to wait a long time (or need to return) to receive results. As a result, follow up can be impeded and care or treatment can be incomplete.

The only inexpensive, rapid tests currently available for STIs are for syphilis and HIV. The syphilis test is already in use in some resource-limited settings. The test is accurate, can provide results in 15 to 20 minutes, and is easy to use with minimal training. Rapid syphilis tests have been shown to increase the number of pregnant women tested for syphilis. However, increased efforts are still needed in most low- and middle-income countries to ensure that all pregnant women receive a syphilis test.

Several rapid tests for other STIs are under development and have the potential to improve STI diagnosis and treatment, especially in resource-limited settings.

Treatment of STIs

Effective treatment is currently available for several STIs.

• Three bacterial STIs (chlamydia, gonorrhea, and syphilis) and one parasitic STI (trichomoniasis) are generally curable with existing, effective single-dose regimens of antibiotics.
• For herpes and HIV, the most effective medications available are antivirals that can modulate the course of the disease, though they cannot cure the disease.
• For hepatitis B, immune system modulators (interferon) and antiviral medications can help to fight the virus and slow damage to the liver.

The resistance of STIs in particular, gonorrhea to antibiotics has increased rapidly in recent years and has reduced treatment options. The emergence of decreased susceptibility of gonorrhea to the “last line” treatment option (oral and injectable cephalosporins) together with antimicrobial resistance already shown to penicillins, sulphonamides, tetracyclines, quinolones, and macrolides make gonorrhea a multidrug-resistant organism. Antimicrobial resistance for other STIs, though less common, also exists, making prevention and prompt treatment critical.

Source & Credits: World Health Organization

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