July 17, 2007 -- More than 2 million people in the U.S. are infected with chlamydia and 250,000 have gonorrhea, according to a government prevalence estimate for the two sexually transmitted diseases.
Rates of both STDs were disproportionately high among adolescents and African-Americans and among people who had been previously infected with chlamydia or gonorrhea.
The findings present the most comprehensive snapshot of chlamydia and gonorrhea infection in the U.S. ever reported, CDC medical epidemiologist S. Deblina Datta, MD, tells WebMD.
CDC researchers studied 6,632 people between the ages of 14 and 39 participating in a national health survey from 1999-2002. All the participants provided urine samples, which were tested for the presence of chlamydia and gonorrhea bacteria.
"We confirmed that both chlamydia and gonorrhea still pose significant health risks in the United States and that disparities exist, especially with regard to the prevalence of gonorrhea among whites and blacks," Datta says.
Chlamydia and Gonorrhea Figures
Of the diseases that by law must be reported to government health officials, chlamydia and gonorrhea respectively rank No.1 and No. 2 in incidence.
In women, untreated chlamydia or gonorrhea infection can cause pelvic inflammatory disease, infertility, and pregnancy complications such as low-birth-weight babies, premature birth, and serious infections in newborns.
According to the newly published CDC estimate, two out of every 100 (2.2%) adolescents and adults under age 40 in the U.S. are infected with chlamydia and just under one in 400 (0.24%) have gonorrhea.
Across all ethnic groups, adolescents and young adults had the highest infection rates and roughly half of those with gonorrhea infections also had chlamydia.
Overall, the prevalence of chlamydia infection was similar among men and women. But the infection rate was roughly four times higher for African-Americans than for whites (6.4% vs. 1.5%) and the disparity was even higher for gonorrhea.
The chlamydia rate was 17% for females who had reported a previous chlamydia or gonorrhea infection within the past year.
Screening for Chlamydia and Gonorrhea
CDC currently recommends annual chlamydia screenings for all sexually active women under the age of 26, and annual screenings for older women with risk factors for the STD, such as a new sex partner or multiple partners. Screening is also recommended for all pregnant women.
Routine screening for gonorrhea is also recommended for women with a high risk for infection, such as sex workers and women with new or multiple sex partners.
The findings suggest that current chlamydia and gonorrhea screening recommendations are adequate, assuming they are implemented, Datta says.
"If screening recommendations are properly applied they will be effective, but we know that this isn't happening consistently," she says. "This needs to be a focus of STD prevention."
The prevalence analysis appears in Tuesday's issue of the Annals of Internal Medicine.
Penicillin-Resistant Gonorrhea Down
In a separate study, published in the same issue of the journal, another group of CDC researchers reported that the prevalence of penicillin-resistant gonorrhea appears to be declining, while resistance to antibiotics in the class known as fluoroquinolones is on the rise.
In April of this year the CDC recommended that fluoroquinolones no longer be used to treat the infection because of rising resistance among both heterosexual and gay men.
Now only one class of antibiotics -- cephalosporins -- is recommended for the treatment of gonorrhea.
In a press release, CDC officials noted that the declining treatment options underscored the need for new drugs to treat the infection and for better ways to monitor drug resistance.
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