Group B Streptococcus (GBS)
Group B Streptococcus (GBS) is a leading cause of sepsis and meningitis in young infants worldwide—often affecting babies just a few hours old. In high-resource countries, women who test positive for carrying the GBS bacterium receive intravenous antibiotics during labor, drastically reducing the chances of GBS passing to the newborn and causing early-onset disease. In low-resource countries, however, GBS screening is all too often unavailable for women, which means that they are unlikely to receive preventive antibiotic treatment during labor. Moreover, babies born healthy can contract the disease in the weeks or months following birth without any clear cause—cases where maternal antibiotic prevention is of little help. GBS may also play a role in miscarriage and stillbirth. A vaccine against GBS delivered to pregnant women could eliminate the chance of newborn infection and provide babies with the critical protection they need to survive infancy.
On the PATH website
- GBS disease is caused by the bacterium Streptococcus agalactiae.
- People of any age can contract the bacterial infection, but infants under three months of age are at the highest risk of severe complications and death.
- GBS can cause sepsis, meningitis, and pneumonia in newborns.
- Babies who survive the infection are often left with lifelong disabilities such as deafness, blindness, and developmental delays.
- One in four women carry the GBS bacterium in their vagina or rectum, which can be passed from mother to child during labor and birth.
- In some high-resource countries, women 35 to 37 weeks pregnant are tested for carriage of the disease; those who carry it receive antibiotic treatment during labor, drastically reducing the chances of GBS passing to their newborn.
- There are two main types of GBS disease in newborns—early-onset and late-onset. Early-onset disease occurs during the first week of life, often affecting babies just a few hours old. Late-onset disease occurs from the first week through the first three months of life, and is often contracted without any clear cause—cases where maternal antibiotic prevention is of little help.
- No licensed vaccine against GBS currently exists.
- Pfizer and GlaxoSmithKline (GSK) both have vaccine candidates against GBS in the development pipeline. Pfizer has planned a Phase 1/2 clinical study of a multivalent vaccine candidate and GSK has taken a trivalent vaccine candidate through a Phase 2 clinical study.
- Clinical study is focused on polyvalent, conjugate vaccines targeting the most common types of GBS; research shows that a pentavalent vaccine has the potential to protect against more than 90 percent of the disease globally.
- A vaccine against GBS is important to prevent against cases of late-onset disease with no clear cause, and in developing country settings where antibiotic treatment during labor is not feasible.
- US Centers for Disease Control and Prevention. Group B Strep (GBS).
- PATH. Protecting Mother and Baby From Infectious Diseases.
Page last updated: March 2017.
Photo: PATH/Gabe Bienczycki.