Estimated incidence and prevalence of genital Chlamydia trachomatis infections in the United States, 1996.
OBJECTIVE
Because genital Chlamydia trachomatis infections and their sequelae have a major impact on individuals and the health care system, it is important to periodically update estimates of chlamydia incidence and prevalence in the United States.


METHODS
Chlamydia incidence and prevalence were estimated using: (1) a method based on estimates of population-specific chlamydia prevalence, and (2) a method based on the chlamydia-to-gonorrhea case rate ratio.


RESULTS
Using the prevalence-based method, point prevalence among persons 15 to 44 years of age was estimated to be 1.6 million chlamydial infections, and annual incidence, 2.4 million cases per year. Using a method based on the ratio of reported gonorrhea to chlamydia, incidence was estimated to be 2.8 million infections per year, and prevalence, 1.9 million. Adjustment for sensitivity of diagnostic tests yielded annual incidence estimates of 2.5 to 3.3 million infections.


CONCLUSIONS
Using two methods, we estimated the annual incidence of chlamydial infections in the United States among persons 15 to 44 years of age to be approximately 3 million infections. Critical data needed for more precise estimates include: sensitivity of current diagnostics, better data on infections in males, the current extent of underdetection and underreporting, and better data on duration of infection in men and women.
Groseclose
S L
SL
Division of STD Prevention, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. slg0@cdc.gov
Zaidi
A A
AA
DeLisle
S J
SJ
Levine
W C
WC
St Louis
M E
ME
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002690:Chlamydia Infections / Q000453:epidemiology*; D002692:Chlamydia trachomatis; D004812:Epidemiologic Methods; D005260:Female; D005831:Genital Diseases, Female / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D011159:Population Surveillance; D015995:Prevalence; D014481:United States / Q000453:epidemiology