By Fergus Walsh
BBC medical correspondent
Clinical trials have begun of a vaccine against one of the biggest childhood killers, meningitis B.
The vaccine could prevent deaths and disability
A group of 150 babies in the UK are being immunised at home with the new vaccine.
It is hoped the new jab will prevent hundreds of deaths and disabilities that meningitis B causes each year.
Three vaccines against other common infections that cause meningitis are already given to babies as part of the childhood immunisation programme.
Babies are immunised against Hib, pneumococcol and meningitis C in their first year of life.
That has left meningitis B as the last major type to crack; the bug which causes 90% of all cases.
Meningitis is one of the most feared of all childhood diseases. In the illness, the membranes that cover the brain and spinal cord become inflamed.
The viral form is milder and usually needs no treatment, but bacterial meningitis can be life-threatening and requires emergency treatment.
The bacterial infection can kill within hours.
The symptoms can range from fever, vomiting, muscle pain, cold hands and feet to a rash that will not fade.
Nine-week-old baby Carys, from Oxfordshire, is one of the infants taking part in the trial.
Her mother, Karla Coletta, explained why she agreed to take part.
"Meningitis is the only illness apart from cancer that scares me.
"It would just put my mind at rest that there is a vaccine which can provide protection against it."
Dr Andrew Pollard from University of Oxford is co-ordinating the trial. He says an effective vaccine would be a huge step forward.
"It's been a particularly difficult road to develop a vaccine because this is a germ that is very variable and it would transform paediatrics. Junior doctors would no longer worry that every children they had sent home with a virus had meningitis B," he said.
The key question is how effective is the vaccine, which will not be known until next summer when the first results of this trial emerge.