An antibiotic developed decades ago could soon become a preventative pill in the United States to combat sexually transmitted infections (STIs). Doxycycline, taken after unprotected sex, has shown in clinical trials to significantly reduce the risk of infection for three diseases: chlamydia, gonorrhea and syphilis.
The Centers for Disease Control and Prevention (CDC), the main US federal health agency, plans to recommend this new approach to contain epidemics affecting vulnerable groups. Concerns include antibiotic resistance as well as the need for new options for public health.
The planned recommendations, expected this summer, could primarily target high-risk groups such as gay men and transgender women with a history of infections. Some doctors already prescribe doxycycline as a preventative measure. The number of cases of chlamydia, gonorrhea, and syphilis in the United States has increased in recent years, reaching 2.5 million in 2021. This is partly due to decreased condom use due to increasing use of PrEP (pre-exposure prophylaxis) for HIV.
Doxycycline has shown effectiveness in clinical trials, reducing infections significantly, particularly for chlamydia and syphilis. However, concerns about the development of antibiotic resistance persist, particularly for gonorrhea.
Researchers observed higher rates of resistant bacteria in people treated with doxycycline, but this could simply mean that this antibiotic is less effective against these resistant strains rather than being the cause. Doctors are seeking to preserve the effectiveness of existing antibiotics, such as ceftriaxone, while exploring new preventative methods.
Frank Verain
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