Group A Streptococcal Infections

Research

Through research, health experts have learned that there are more than 120 different strains of group A streptococci bacteria, each producing its own unique proteins. Some of these proteins are responsible for specific group A streptococcal diseases.

With the support of NIAID, scientists have determined the genetic sequence, or DNA code, for five strains of the group A streptococcus bacterium.

By studying its genes, scientists can learn which proteins are responsible for virulence—crucial information that will lead to new and improved drugs and vaccines.

NIAID supports research to develop a group A streptococcus vaccine, and several candidate vaccines are in various phases of development. While some scientists are conducting animal model studies to obtain data to pursue clinical trials in humans, other scientists are close to evaluating group A streptococcus vaccine candidates in Phase I clinical trials.

As a result of NIAID-supported research, the first group A streptococcus vaccine clinical trial in 30 years was started. The vaccine was well tolerated by patients and has led to further clinical evaluation of a similar vaccine candidate.

An effective vaccine will prevent not only strep throat and impetigo but also more serious invasive disease and post-infectious complications like rheumatic fever.

Vaccine development efforts include NIAID-supported epidemiological studies

• To determine the extent of group A streptococcal disease
• To characterize group A streptococcal strains causing illness in the United States and developing countries

NIAID, in collaboration with the Centers for Disease Control and Prevention and the World Health Organization, has developed standard definitions and methods for surveillance of group A streptococcal diseases to determine current burden of disease information.

This was accomplished by meetings with experts in the group A streptococcal research community that included research scientists, academic investigators, clinicians, and public health officials.

Protocols

Two field protocols were developed for NIAID clinical studies in order to compare epidemiological data across different geographical locations. See Protocols for Surveillance of Streptococcus pyogenes Infections and their Sequelae.

• One protocol focused on acute streptococcal disease: “Standardization of Epidemiological Protocols for Surveillance of Acute Diseases Caused by Streptococcus pyogenes: Pharyngitis, Impetigo and Invasive Diseases”. The following publications describe data generated using this document:
  • Steer AC et al. Prospective Surveillance of Invasive Group A Streptococcal Disease, Fiji, 2005-2007. EID 2009 Feb;15(2):216-22
  • Steer AC et al. Prospective Surveillance of Streptococcal Sore Throat in a Tropical Country. Pediatr Infect Dis J. 2009 Jun;28(6):477-82
• The other protocol focused on the after-effects of acute infections. “Standardization of Epidemiological Protocols for Surveillance of Acute Rheumatic Fever, Rheumatic Heart Disease and Post-streptococcal Glomerulonephritis. The following publication describes data generated using this document:
  • Steer AC et al. Acute rheumatic fever and rheumatic heart disease in Fiji: prospective surveillance, 2005-2007. MJA 2009; 190 (3): 133-135
  • Paar J et al. Prevalence of Rheumatic Health Disease in Children and Adults in Nicaragua. Am J Cardiol, 2010 Jun 15; 105 (12): 1809-1814

These protocols are posted to make them more widely available to the scientific community and were used at NIAID-supported clinical sites in Mali (Africa), Leon (Nicaragua), and Suva (Fiji) to obtain epidemiological data that will be useful for designing future vaccine clinical trials. When all data from these clinical studies have been collected and analyzed, the protocols will be reviewed and updated as appropriate.

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