health

Chlamydia is the most common sexually transmitted disease in the United
States. The Centers for Disease Control and Prevention (CDC) estimates
that there are as many as 4 million Americans infected with chlamydia,
with 2.8 million new infections each year. It is highly likely that the real
numbers are higher because many people with chlamydia—75 percent
of infected women and 50 percent of infected men—do not have any
noticeable symptoms and are not screened by a doctor. The World Health
Organization (WHO) estimates that about 89 million people are infected
with chlamydia worldwide, with about 8 million permanently blind as a
result of trachoma.

Some groups of people are at greater risk than others of being
infected with chlamydia. High-risk groups in the United States include:

• Young adults of either sex
  
• Adolescent girls between the ages of fifteen and nineteen
  
• African Americans
  
• People who have unprotected sex or do not use barrier methods of
  birth control (condoms or diaphragms)
  
• Homosexual men, particularly those who are HIV-positive or
  abuse drugs or alcohol
  
• People living in large cities
  
• People with low income or little education
  
• People who have a large number of sexual partners