Posted on August 19, 2019

Researchers at Weill Cornell Medicine-Qatar (WCM-Q) have discovered unexpectedly high levels of chlamydia infection among the general population in the Middle East and North Africa (MENA), and higher levels still among women in the region who are infertile or suffer pregnancy complications.

The research, published in the prestigious UK journal The Lancet Global Health, reports that chlamydia infection appears to be responsible for a substantial proportion of infertility cases among women in this part of the world.

Chlamydia is a bacterial reproductive tract infection that is often symptomless, and which is usually, but not always, transmitted sexually. When a woman acquires the infection, the pathogen travels to the internal reproductive organs, damaging them and making it difficult for an infected woman to conceive a baby. If an infected woman does manage to conceive, the infection can cause miscarriage or preterm labor and delivery, or the baby can be infected leading to low birth weight or death of the fetus before delivery. Chlamydia can also cause neonatal infections such as conjunctivitis and pneumonia in babies after birth.

Because chlamydia is often symptomless, most women are unaware of their infection unless they have been screened using a diagnostic test. If diagnosed, chlamydia infection can be easily treated with a course of a specific antibiotic. Despite chlamydia infection being well-studied globally, the rates in the MENA region were poorly known before the WCM-Q study, which was conducted by the college’s Infectious Disease Epidemiology Group (IDEG). The research, which was based on an in-depth multi-year investigation using data from more than 250,000 individuals from 20 out of the 23 MENA countries, marks the first time in which a detailed characterization of chlamydia infection levels in the region has been reported.

“Rates of infertility among women in MENA are the highest worldwide, but the causes of such rates remain poorly understood. It was striking for us to discover that chlamydia infection appears to be a major cause of infertility in this region,” said Hiam Chemaitelly, co-lead author of the study and Senior Epidemiologist at WCM-Q.

The study indicated that three percent of the population of the MENA region is currently infected with the chlamydia bacteria, a rate comparable to that found in other regions. The rates of infection were also found to be stable for at least the last three decades. Meanwhile, the infection rate in infertile populations was 11 percent and the rate in women who had experienced miscarriage was 12 percent, highlighting the toll of this pathogen on women’s reproductive health. Despite this pressing health problem, there are virtually no public health programs in MENA countries to tackle chlamydia infection.

“Our study shows that even though chlamydia may be hidden to the public eye, its complications are easily seen, but are not linked to the real cause. The impact of these complications on women are far-reaching, especially in a region where fertility, children and family values are highly regarded,” said Dr. Alex Smolak, co-lead author of the study and Research Fellow at WMC-Q. Although chlamydia screening and treatment programs are a standard practice in many developed countries, such programs very rarely exist in the MENA region. The study indicated that the virtual absence of these programs is probably behind the unexpectedly high levels of this infection; infected individuals carry the bacteria for a long time, thus passing the infection to more individuals before the infection is cleared.

“When we started this study nearly a decade ago, the last thing we expected was to be confronted with these high chlamydia levels,” said Dr. Laith Abu-Raddad, principal investigator of the study and Professor of Healthcare Policy and Research at WCM-Q. “We cannot escape the need for programs to tackle this infection, which are common practice in other parts of the world. Otherwise the region will continue to endure serious health and social complications, and will fail to reach the World Health Organization’s goal of eliminating this infection as a public health threat by 2030.”

The study, ‘Epidemiology of Chlamydia trachomatis in the Middle East and North Africa: a systematic review, meta-analysis, and meta-regression’, was conducted at WCM-Q with funding from Qatar National Research Fund, a Qatar Foundation member, through the National Priorities Research Program (NPRP 9-040-3-008). Funding was also provided by the WCM-Q Biomedical Research Program (BMRP).

Link to study

Key scientific findings of the study

  • About three percent of the population of the Middle East and North Africa region is infected by chlamydia without being aware of their infection.
  • The rates of infection are even higher in infertile populations (11 percent) and in women who have experienced miscarriage (12 percent).
  • Women in fertility clinics and with pregnancy complications had higher rates of chlamydia, suggesting a link between this infection and infertility and pregnancy complications in the MENA region, yet the infection’s disease burden is neglected and poorly recognized.