A Vaccine For Strep A May Be On The Horizon

A vaccine that protects against Step A could soon be on the way after scientists apparently made a breakthrough in understanding how the body fights off the bacteria.

Strep A usually causes a mild infection, like strep throat, impetigo or scarlet fever. But in exceptionally rare cases, it can lead to a deadly disease. 24 children have died in the UK over the past few months.

This has been the time of year that school children have been given their annual flu vaccinations – a live attenuated influenza vaccine [LAIV] adminsitered via a nasal spray.

According to the UK Health Security Agency (UKHSA) the nasal spray vaccine may also help protect against strep A infections.

However, it’s also been found that live attenuated influenza vaccine enhances the colonization of Streptococcus pneumoniae and Staphylococcus aureus in mice.

The Mail Online reports: As it stands, the infection can be easily treated with antibiotics if caught early. However, if the bacteria were to become resistant to the drugs, it would post a ‘major public health threat’, experts say.

But Swedish researchers have now found an antibody that fights off Strep A bacteria in an unusual way, which they believe could be key to developing a vaccine.

The researchers, at Lund University, studied the blood of patients who had recovered from a severe Strep A infection to determine how their immune system had fought-off the bacteria.

They mapped the antibodies that their bodies produced when they were unwell with Strep A.

This allowed them to spot those that could be harnessed for medicines or vaccines once an infection has occurred.

Until now, researchers using this method have failed to develop antibody-based treatments that work against Strep A, according to the team.

However, the Swedish group found an antibody that works in a ‘rare’ way against Strep A that has ‘never been described before’ and ‘could explain why so many vaccine attempts have been unsuccessful’.

Antibodies are shaped like the letter Y. The one they spotted, called Ab25, used its two ‘arms’ to hook onto two different parts of a protein on the surface of the Strep A bacteria – called the M protein.

Where this unique process was spotted, the body was able to mount a strong response to the bacteria.

Usually, antibodies use one arm to bind to a single site, the researchers said. But this process is ineffective against Strep A.

Dr Wael Bahnan, an immunologist at Lund and one of the study authors, said: ‘This opens up possibilities where previous vaccine attempts have failed and means that the monoclonal antibody we used has the potential to protect against infection.’

The team conducted further tests on the antibody in animals and found it was able to produce a ‘strong immune response against the bacteria’.

They have now applied for a patent based on their findings, published in the journal EMBO Molecular Medicine, and hope the antibody will eventually lead to Strep A treatments and vaccines.