By Gene Emery
(Reuters Health) – Innoculating infants with the Bexsero vaccine against group B meningitis provides protection from the deadly infection for at least two years in 75% of young children, according to results from the first large real-word test of the vaccine, conducted in the United Kingdom.
Meanwhile, an Australian study is showing that while the vaccine also works in teens, it does not extend “herd immunity” to unvaccinated children, as some vaccines do.
Both studies appear in The New England Journal of Medicine.
Meningitis “is one of the fastest, most vicious infections you can have. The child can be sneezing in the morning and be dead in the evening, even if they get to the hospital,” said Dr. Shamez Ladhani, a clinical epidemiologist at Public Health England and a coauthor of both papers.
Even with antibiotics, 10% to 15% of patients die and up to 19% of survivors have long-term disabilities. About one third of cases of meningococcal disease in the United States are caused by group B bacteria.
“Really, the only way to protect is vaccination,” Ladhani said in a telephone interview. That’s why the UK began a mass vaccination program in 2015, the first country to do so. Babies receive two doses of the vaccine, the first at 8 weeks and the second at 16 weeks, followed by a booster at 12 months.
The UK study, based on the first three years of that program, provides important new information about the effectiveness of the vaccine, which is sold by GlaxoSmithKline and also known as 4CMemB.
There were 63 cases of meningitis B after the vaccination program compared with 253 cases that were expected during that period, based on previous rates.
That translates into a 75% reduction in disease among children who were fully eligible for vaccination.
“This is good news and highlights the real-world effectiveness of 4CMemB,” Dr. Lee Harrison of the University of Pittsburgh and Dr. David Stephens of Emory University School of Medicine write in an accompanying editorial.
Ladhani said he hoped the new findings, along with results of other tests expected from researchers in Portugal and Italy, will encourage other countries to initiate population-wide vaccination programs for the very young and teenagers beginning around age 15, the two groups most prone to meningitis.
The second study, performed in South Australian teens in grades 10 to 12, adds to evidence that the vaccine only protects the vaccinated.
That test was done at 237 schools, half of which vaccinated children in grades 10 and 11; the rest were vaccinated at grade 12, allowing those students to serve as the control group. Each child got two doses two months apart.
Bacteria responsible for meningitis often thrive in the nose and throat without ever causing symptoms. “Meningitis B wants to live in your nose and live happily ever after,” Ladhani noted. Only rarely does it cause illness.
The hope was that vaccinated teens who were not yet infected would stay that way. But at the 12-month mark, 2.13% of the students vaccinated early had acquired some type of meningitis bacteria versus 2.07% in the control group.
Nonetheless, during the two years prior to the Australian study, there had been 12 cases of meningococcal B disease among students age 15 to 18. During the two years of the test, there were none.
The lack of herd protection conferred by the vaccine “is the bad news,” Harrison and Stephens write. One other piece of good news is that the vaccine appears to be extremely safe.
After three years and more than 3 million doses, “we find no concerning safety signals at all,” said Ladhani. Babies often react to the vaccination with fever, pain, redness and swelling around the arms but that problem has been prevented by routinely treating the babies with acetaminophen, beginning at the time of the shot.
The lead author of the Australian study, Dr. Helen Siobhan Marshall of the University of Adelaide, did not respond to a request for an interview.