A team of international scientists has discovered common molecular targets across multiple strains of Group A Streptococcus bacteria (Strep A), offering hope for the development of a global vaccine.

Under a ten-year project, researchers from the UK’s Wellcome Sanger Institute and University of Cambridge, as well as the Peter Doherty Institute for Infection and Immunity and the University of Queensland in Australia sequenced the DNA of more than 2,000 Strep A strains from 20 countries.

Some common molecular targets were observed to be present in samples from all 20 countries, which is expected to facilitate a potential global vaccine against the bacteria.

Project lead author Dr Mark Davies said: “Using large-scale genomic sequencing, we identified the existence of more than 290 genetically different lineages of clinically important Strep A, highlighting the challenges of designing an effective global vaccine.

“However, using all the data we collected, we narrowed down common genes in almost all strains of Strep A globally. This is a tremendous step forward in identifying what may work as a global vaccine candidate.”

Strep A is considered one of the top ten causes of infectious disease-related deaths globally. It is estimated that the bacteria is responsible for more than half a million deaths annually.

Currently, an effective vaccine against the bacteria is not available, and development of one has been difficult due to the presence of a variety of strains.

Wellcome Sanger Institute and University of Cambridge professor Gordon Dougan said: “Millions of people around the world are affected by Strep A.

“This is a tremendous step forward in identifying what may work as a global vaccine candidate.”

“It can cause a range of conditions, from sore throats and outbreaks of scarlet fever in the UK, to infections leading to rheumatic heart disease in populations such as the Australian Aboriginal population.

“In addition to aiding research into a vaccine, genomic data from our study will help researchers understand how Strep A causes disease and why it is different in high-income areas to endemic regions.”