Bacteria called Group B Streptococcus or Streptococcus agalactiae (Group B strep, GBS) commonly live in people’s gastrointestinal and genital tracts. Most of the time, the bacteria are not harmful and do not make people feel sick or have any symptoms. Sometimes, however, the bacteria invade the body and cause certain infections, which are known as GBS disease. GBS bacteria can cause bacteremia (bloodstream infection) and sepsis (the body’s extreme response to an infection), meningitis, pneumonia, bone and joint and skin and soft-tissue infections. An invasive GBS infection is one that involves blood or internal organs, whereas a noninvasive infection could involve skin or other soft tissue, the urinary tract or bones and joints.

Previous studies describing the burden of GBS infection in adults have primarily focused on invasive disease because existing surveillance systems rely on blood culture collection. In the new study, however, non-invasive disease was three to four times more common than invasive disease, suggesting that adult GBS burden is considerably greater than previously recognized. Of the infections reviewed, 79% were non-invasive. In 60% of the infections, GBS was identified as the only pathogen.

“These new data suggest that the burden of GBS infection is considerably greater than previously recognized in earlier surveillance studies that only focused on invasive disease, ” said Julio Ramirez, MD, chief of the Division of Infectious Diseases at UofL. “Importantly, we found that the rates of GBS infection in this study are comparable to that of other adult infections for which vaccines are routinely recommended, which underscores the need for developing approaches for preventing this infectious disease among an aging adult population.”

In conducting the study, the researchers reviewed laboratory and medical records from six hospitals in Louisville between Jan. 1, 2014 and Dec. 31, 2016. Louisville’s population is generally similar to the United States in terms of demographics and prevalence of underlying chronic medical conditions.

Rates of GBS-associated hospitalization were significantly higher in adults 65 years and older, African Americans and people with underlying chronic medical conditions such as obesity, diabetes, chronic renal disease and coronary artery disease. The finding that obesity and diabetes put patients at increased risk for GBS-associated hospitalization is especially noteworthy given that recent Centers for Disease Control and Prevention reports have highlighted that 42% of U.S. adults are obese and that as many as 34 million American adults (roughly 13% of all U.S. adults) have diabetes, with another 88 million having pre-diabetes.

Additional findings from the study included the following:

• Annual rates of GBS infection in African American adults were 2.6 times higher than in white adults, or 157 per 100,000 in African American vs. 60 per 100,000 in white adults.
• Compared with the general population, annual GBS infection rates were 2 to 6 times higher among adults with underlying chronic medical conditions, such as chronic kidney disease, diabetes, obesity or heart disease.

“This type of study, evaluating both invasive and non-invasive GBS infections, is essential for understanding the full spectrum of GBS disease burden among adults,” said John M. McLaughlin, PhD, Global Epidemiology and Scientific Affairs Lead, Pipeline Vaccines, Pfizer Inc., and the lead study author. “These data should aid health care providers with clinical decision-making. Our population-based study gives the first estimates of total annual GBS burden in the United States, emphasizing the importance of preventive efforts in the growing population of adults who are older or have chronic medical conditions, and will inform future vaccination strategies.

In January, Pfizer launched its , a global program of collaborations with academic institutions to conduct real-world epidemiologic research to accurately identify and measure the burden of specific vaccine-preventable diseases and potentially evaluate vaccine effectiveness in adults. At that time, the UofL Division of Infectious Diseases was designated as the first . This collaboration is aimed at determining the human health burden of important infectious diseases and potential vaccine effectiveness

The GBS collaborative study between UofL and Pfizer was completed prior to the university being named as Pfizer Vaccine’s first Center of Excellence site.

UofL has been designated the first Center of Excellence by Pfizer Vaccines.

“UofL’s Division of Infectious Diseases has a rich history of collaboration with Pfizer through the successful implementation of numerous clinical epidemiological research studies. We are excited to formalize a long-term collaboration that builds on these past successes,” said Julio Ramirez, MD, chief of the Division of Infectious Diseases at the .

The Center of Excellence, directed by Ramirez, is a collaboration between the university and the pharmaceutical corporation aimed at determining the human health burden of important infectious diseases and potential vaccine effectiveness. The data will provide robust evidence to national health officials and independent policy makers who develop recommendations for the use of vaccines in immunization programs worldwide. Studies will take place in hospitals, long-term care facilities and the community.

UofL is the first Center of Excellence selected by Pfizer Vaccines Medical Development and Scientific/Clinical Affairs to be part of an international network of epidemiological research organizations. This designation is for a period of three years with an option for renewal. Pfizer selected UofL because of the university’s exceptional capabilities for conducting population-based surveillance and clinical research that engages multiple health care facilities, health care personnel, industry and communities-at-large.

“Pfizer has had an outstanding working relationship with the University of Louisville for more than 10 years,” said Luis Jodar, PhD, chief medical and scientific affairs officer, Pfizer Vaccines. “The quality of disease burden evidence varies widely worldwide. Deriving accurate and credible population-based incidence estimates require comprehensive surveillance to identify cases of diseases within a well-defined and well-characterized geographic area. Thanks to UofL’s excellent network of research partners, the population available for research studies in Louisville can provide the data to derive estimates of disease burden that can be generalized nationally.”

The demographics of Jefferson County, Kentucky, are similar to the United States in general, including racial and ethnic make-up, socioeconomic status, and the proportion of rural and urban populations.

The research studies conducted as part of the center may lead to economic growth and development for the city of Louisville and the Kentuckiana region, including jobs and educational opportunities in the health care industry.

“This collaboration will provide increased visibility for the university on a global scale, making UofL attractive for high-caliber researchers and research grants,” said Neeli Bendapudi, PhD, president of UofL. ”It also presents an exceptional opportunity for our researchers to improve the human condition by helping to reduce the burden of infectious diseases worldwide by generating data that will inform governments and health care policymakers.”

Pfizer studies anticipated for UofL include population-based surveillance of infectious diseases including Streptococcus pneumoniae, a bacteria which causes pneumonia and other infections, Clostridioides difficile, a bacteria that causes severe diarrhea and colitis, and respiratory syncytial virus (RSV), a common virus associated with mild cold-like symptoms but can cause severe infection in some people, including older adults. Visit for additional information on these diseases and two Center of Excellence studies already underway at UofL:

• The City of Louisville Diarrhea (CLOUD) study launched in September 2019. Pfizer will be providing up to $6.5 million in funding for a one-year study of the incidence of diarrhea among Louisville-area residents.
• The Louisville Pneumonia study is up to $4.5 million in funding provided by Pfizer for a one-year study of the incidence of pneumonia among adults in Louisville that launched in November 2019.

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