GBS can cause serious infection of the blood, lungs or brain
Expectant mothers booking into a Surrey maternity unit are to be asked to take part in a study aimed at creating a vaccine which could save babies' lives.
Group B Streptococcus (GBS) affects 700 babies a year in the UK and is carried by about one in four women.
It poses no danger to mothers but is the most common cause of life-threatening infection in newborns.
The study at the Royal Surrey County Hospital in Guildford aims to swab 3,000 mothers over an 18-month period.
It begins on Monday and the results will be sent to the Health Protection Agency laboratory in Colindale, north-west London.
"At the moment it is not clear how to prevent GBS infection," said Royal Surrey obstetrics and gynaecology consultant Dr Karen Morton.
"There are 10 strains of the bacteria and this study aims to identify the most common strain."
GBS can be passed from mother to baby during pregnancy or labour and can cause serious infection of the blood, lungs or brain in the newborn. About one in eight infected babies dies.
It is expected to take scientists about 10 years from the end of the study to create a vaccine.
The jab would be given to girls in their early teens to protect them and their babies from GBS infection in the future.
"Mothers who take part in this study will potentially help to protect their children's babies from GBS infection in the future," said Dr Morton.
The Royal Surrey, which is one of only two centres taking part in the study, was selected because it took part in a similar project to find out how many of its pregnant women were carriers.
Mothers who want to take part in the study will be asked to take their own swabs at 34 weeks and have an additional blood test.