Vaccine

Vaccine Against 'strep throat' Possible: Study

It may be possible to make a safe vaccine against the type of bacteria best known for causing 'strep throat' and rheumatic fever, US-based researchers report. The bacteria that causes serious disease can be altered slightly into a form that may work as a vaccine, the team at the University of California, San Diego, reported.

Group A streptococcal infections affect more than 600 million people each year and kill 4,00,000 globally. Untreated strep throat infections can cause rheumatic fever, an often deadly inflammation of the heart. In countries where antibiotics are not easily available, rheumatic fever remains common and can weaken the hearts of survivors for life. Group A Streptococcus, or GAS, can also cause the 'flesh-eating' syndrome called necrotising fasciitis and blood-borne infections, including toxic shock syndrome.

It has been tricky to try to design a vaccine against GAS because the antigen— the part of the bacteria most easily recognised by the body's immune system— is also the most toxic part. It causes inflammation and the dangerous over-reaction of the immune system that leads to heart damage.

Partho Ghosh and colleagues managed to get an image of this tiny structure, called M1 protein. Writing in the journal Science, they said they created a version of M1 that showed potential as a vaccine in mice.

There are two widely used vaccines against other types of strep-Wyeth's Prevnar, given to infants in many countries, and Merck & Co's Pneumovax, given to adults. These vaccines protect against pneumonia, ear infections, and other diseases cause by Streptococcus pneumoniae bacteria. A spokesman at Novartis said the company has a GAS vaccine in the pipeline, but it is in very early stages of testing. The market potential is huge— Wyeth's Prevnar shot has annual sales of $2 billion.

Reuters