A prototype vaccine based on the bacterium Neisseria lactamica is showing promise against group B meningococcal meningitis and septicaemia, the potentially fatal blood poisoning that accompanies the disease.

Scientists have faced difficulties producing a reliable vaccine for meningitis B, which claims around 150 lives annually in the UK, because of the way it invades the human immune system.

The vaccine is being developed by a team at the government's Centre for Applied Microbiology and Research, near Salisbury in Wiltshire, according to an article in New Scientist.

Andy Gorringe, who is leading the research, said: "A child can be dead within a few hours of infection.

"It's a public health priority to get a vaccine."

Dual role

He said he was confident the new vaccine would work against both strains.

He said: "We've evidence it protects against B and C."

He and his colleagues at the Public Health Laboratory Service got the idea of using N. lactamica after seeing reports that people who carry the bacterium appear to be protected from meningitis.

They also knew that N. lactamica has surface features matching those on its lethal relative, N. meningitidis and so could easily prime immunity against the disease itself.

N. lactamica lives harmlessly in the noses of one in 10 babies and young children.

However, the team wanted to make an even safer version, so their prototype vaccine is a mixture of proteins that coat the bacteria.

When it was injected into mice, or sprayed into their noses, the mice survived attacks of meningitis B and C.

The Meningitis Research Foundation has welcomed the development, but warns it is too early to assume it will become an effective treatment.

Nasal spray

The Foundation's spokeswoman Julia Warren said: "It's always encouraging when we hear research is producing positive results, but more research needs to be done.

"It's like putting the pieces of a jigsaw together.

"We aren't there yet, but we are getting there."

She said that even if it is found to be a suitable candidate on which to base a vaccine, it could be at least five years before it is licensed because it will have to undergo rigorous clinical trials.

Mr Gorringe hopes the vaccine would come in the form of a nasal spray for very young infants.

He and his colleagues are in discussion with vaccine manufacturers to take the project further.

In 1999, when the meningitis C vaccine was introduced, there were 996 cases of the disease, but by 2001, this had dropped to 322.