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Group B Strep Case-Control Study


The Emerging Infections Program (EIP), in partnership with the Connecticut Department of Public Health (CT DPH), Centers for Disease Control and Prevention (CDC) and the Bill and Melinda Gates Foundation, is conducting a multi-site research study to understand how a pregnant woman’s immune system helps protect her baby from a group B Streptococcus (group B strep) infection. The purpose of this study to prevent GBS infections in the future, possibly with the help of a vaccine for pregnant women created using results from this study.

Group B strep, or GBS, is a bacterium that can cause serious infections in young babies and is the leading cause of morbidity and mortality in young infants under 3 months of age worldwide. Women colonized with GBS bacteria can pass GBS bacteria to their babies during the birth process. GBS can cause babies to develop infections after birth such as bacteremia (blood infection), pneumonia (lung infection) and meningitis (infection of the tissue surrounding the spinal cord and brain), which can cause death. Such infections can develop days or months after birth. Currently, the available prevention measure is to give women colonized with GBS intravenous antibiotics during labor.

During pregnancy, a women’s immune system passes protective antibodies to the baby. What we hope to understand is how a pregnant woman’s immune system helps protect her baby from group B strep infections.

The development of a GBS vaccine for pregnant women could potentially prevent GBS infections in the future. However, more needs to be known about the immunologic targets of GBS infection for this to happen.

Goals and Objectives

  • Estimate antibody concentrations associated with an 80% reduction in odds of GBS disease among infants for the two most common serotypes of GBS.
  • Inform the development of a vaccine for mothers to protect newborns from GBS infection.


The EIP is recruiting new mothers for a case-control laboratory study looking at the differences in antibody type, function, and concentration in newborns born to GBS positive mothers who contract severe GBS infection and newborns born to GBS positive mothers who do not contract severe GBS infection.

If you would like more information on the study please read the Study Information Sheet

Clinical Partners

Katherine Kohari, MD
Medical Director
Maternal-Fetal Medicine Outpatient Services
Yale School of Medicine

Sangini S. Sheth, MD, MPH
Associate Medical Director
Women's Center
Yale New Haven Hospital

Generations Ob/Gyn

Project Contact

James Meek, MPH
Associate Director
Connecticut Emerging Infections Program
One Church Street, 7th floor
New Haven, CT 06510