Strep A kills 500,000 people a year, so why isn’t there a vaccine?

A vaccine for strep A may not be very profitable for pharmaceutical companies and there are technical challenges that make such vaccines difficult to develop, but early-stage clinical trials are underway

By Michael Le Page

As of 16 December, at least 19 children have died in the UK in recent months from an invasive infection of strep A bacteria. On a global scale, the bacteria kill more than half a million people each year. Many of these deaths could be prevented by a vaccine – so why don’t we have one?

Strep A is a bacterium known as group A streptococcus, or Streptococcus pyogenes. It is best known for causing a sore throat, so-called strep throat, and scarlet fever. …