Meningitis breakthrough: startling results of potential vaccine

Thursday, May 15, 2008

By Jeremy Laurance

The annual scourge of deaths and severe illness caused by meningitis could be consigned to the history books after scientists announced startling results from trials of a potential vaccine.

In the most significant advance in a decade, researchers say they have obtained powerful immune responses in 150 British infants on whom the vaccine was tested, suggesting it would be protective against the group B type of the disease.

An effective vaccine against meningitis B is the holy grail of meningitis research and could virtually eliminate the devastating bacterial infection from Britain and other European countries. Vaccines against group C meningitis, which was introduced in 1999, and Hib meningitis in 1992, have reduced these causes of the disease by more than 90 per cent.

Ray Borrow, the head of the vaccine evaluation department at the Health Protection Agency in Manchester, said: "I believe we should be very excited indeed. Ten years ago we had success with a vaccine against group C disease but, so far, we have had no real prospect of controlling group B disease.

"There are 20,000 to 80,000 cases of meningitis B globally and roughly 1,200 cases in the UK each year, of which 10 per cent result in death. The prospect of one vaccine that protects infants worldwide against [meningitis B] would be a key achievement in global disease prevention of our time."

Generations of parents have lived in terror of meningitis because it targets the young, strikes with unnerving speed and ferocity, and kills one in 10 of those it infects. Among those who survive, many suffer permanent disability including deafness, neurological problems and loss of fingers and limbs.

The meningitis bacterium lives harmlessly in the noses and throats of one in 10 people but, for reasons that are not fully understood, can erupt into a life-threatening illness that causes inflammation of the membrane around the brain – the "meninges" – and leads to death within hours. With vaccines already available against group C and Hib meningitis, group B is the dominant strain in England, accounting for 84 per cent of the 1,283 cases of meningococcal disease recorded last year.

Developing an effective group B vaccine has presented a much bigger challenge because there are scores of different strains circulating in Europe and most parts of the world. Group B vaccines have been developed and are in use in Cuba and New Zealand but these are only effective against the single strains circulating in those countries.

The new vaccine contains multiple "antigens" – bacterial proteins designed to counter different strains – developed from a study of 85 strains of group B disease. It has so far been tested against three " representative" strains in the current trial.

The 150 babies in the study were given the vaccine at ages two, four, six and 12 months. Laboratory tests on blood samples showed they had better than 85 per cent protection against the three strains. The vaccine, developed by the Swiss multinational pharmaceutical company Novartis, is being tested by an independent team led by Elizabeth Miller, the head of the immunisation department at the Centre for Infections – part of the Health Protection Agency (HPA).

Dr Borrow, who heads the regional HPA laboratory in Manchester and is a member of the team, presented the findings to the European Society of Paediatric Infectious Diseases in Austria yesterday. He said the laboratory results for the group B vaccine were as good as those for the group C vaccine a decade ago "and we have now virtually eliminated group C disease". He added: "I am confident this vaccine will provide broad protection against a range of strains of group B disease. We have full data on three strains and partial data on two more strains which are representative of other components of the vaccine."

A third and final trial, involving hundreds of British children, began earlier this year. Assuming these tests are successful, it would still be " some years" before a vaccine was introduced, Dr Borrow said.

Andrew Pollard, the head of the Oxford Vaccine Group at Oxford University, said the initial results required confirmation to show the extent of the protection provided. "There is still along way to go but a vaccine that gave broad protection against meningitis B would be hugely significant, because this strain causes the most cases and the most deaths from meningitis in Britain and around the world."

A spokesman for the Meningitis Research Foundation said: "This is really exciting news. It is what we have been working towards. If it goes through phase three trials [successfully], we will have cracked the holy grail. It will be virtually the end of the story on meningitis and it will put organisations like ours out of business."

The vaccine was developed using a method called "reverse vaccinology" in which the genetic make-up of a single strain was first decoded. This yielded 600 novel proteins from which the vaccine was constructed, using genetic engineering to pick those that showed the greatest ability to stimulate the immune system.