Strep A vaccine on horizon after key antibody found in recovered patient’s blood
A vaccine for Strep A is on the horizon after scientists discovered a crucial bacteria-fighting antibody in a recovered patient.
Until now, researchers have struggled to produce an effective jab against Strep A, with attempts failing to prevent an infection, which can be deadly in some people.
Scientists at Lund University, in Sweden, studied the blood of patients who had recovered from a serious infection to see whether there was something special about their immune system. In one, they found a special antibody that could be the key to producing a vaccine.
Antibodies look like a capital Y and usually grasp on to an invader using just one arm, acting like a flag that tells the rest of the immune system to take action. But the antibody in the recovered patient latched on using both arms, which scientists found was vital for mounting a strong immune response.
When only one arm was attached, Step A was able to mount effective counter-measures, preventing immune cells from clearing out the infection.
Dr Wael Bahnan, the study author and an immunologist at Lund University, said: “This opens up possibilities where previous vaccine attempts have failed, and means the antibody we used has the potential to protect against infection.”
The team isolated the antibody and tested it in animals, finding that it was able to trigger a strong immune response against the Strep A infection.
Researchers believe previous vaccine attempts failed because they relied on a single arm attachment. They have now applied for a patent and are hoping to eventually create a vaccine.
Pontus Nordenfelt, a study author and associate professor at Lund, said: “What we have seen – and this is vital information – is that the two Y arms can recognise and hook on to two different places on the same target protein.”
Strep A is a bacterium that can be found in the throat or skin. For most people, it lives in their bodies without causing illness.
It mainly spreads through coughs, sneezes or any open cuts, and symptoms can include high temperature, swollen glands and an aching body, sore throat, headache, vomiting, muscle aches and scarlet fever, a rash that feels rough to the touch.
It can also cause the deadly condition iGAS (Invasive Group A Streptococcus). The most recent figures from the UK Health Security Agency show there have been 94 deaths from iGAS infections across England since Sep 12, including 21 children aged under 18.
At the last Strep A peak, which happened in 2017-2018, an outbreak caused the deaths of 27 children over the entire winter.
Currently, infections can only be treated with antibiotics – but there is an ongoing shortage, with around six times more prescriptions issued than normal at this time of year. There are also fears that Strep A may become resistant to treatment, leading scientists to look for another solution.
Previously, doctors have used the blood plasma from recovered patients to treat severe infections with some success, meaning experts knew that some people make powerful antibodies against an infection.
The results were published in EMBO Molecular medicine.
