Getting a Boost to Fight Meningitis

Meningitis B vaccine booster dose improved immune response in children

(RxWiki News) One of the more disabling and fatal bacterial illnesses is meningitis. There are vaccines to protect against many meningitis strains, but not all of them — yet.

A recent study found that a booster dose of a meningitis vaccine considerably improved children's immune response against the disease.

Meningitis is a bacterial illness that causes a serious infection in the brain and/or spinal cord.

There are several different types of meningitis. The vaccine studied in this research protects against strains of meningitis B.

It is not yet available in the US but is being studied by the CDC. It is available in Europe.

"Ask your doctor about the CDC immunization schedules."

This study, led by Matthew D. Snape, MD, of the Department of Pediatrics at the University of Oxford in the United Kingdom, aimed to better understand how a booster shot of a meningitis vaccine affected children's immunity levels against the disease.

The vaccine studied was the multicomponent serogroup B meningococcal (4CMenB) vaccine.

It contains four protein components that occur in many strains of the meningitis B bacteria. It protects against a wide range of the meningitis B strains.

The researchers compared two small groups of 3-year-old children. One group of 17 children had received the 4CMenB vaccine when they were 2, 4, 6 and 12 months old. The other 40 children in the study had never received the 4CMenB vaccine.

The children who had already received the vaccine were given a fifth booster dose. Those who had never received it also received a single dose.

The researchers then measured the immune response to the shot in both groups of children by measuring their "titers."

A titer measurement tells researchers how concentrated the antibodies (disease-fighting cells) against a particular disease are in a person's blood. The higher the titer level, the more immune that person is to the disease.

At the start of the study, 41 to 76 percent of the children who had already received the 4CMenB shots had high levels of titers against four major strains of meningitis B. The percentage varied according to each of the four strains.

Meanwhile, among the control group of children without previous 4CMenB shots before the shot, 63 percent had sufficient titers for one strain, 68 percent for another strain, 3 percent for the third strain and 0 percent for the fourth strain.

After both groups received the 4CMenB shot, the children who had previously received 4CMenB shots had a bigger increase in their titers than the children who were getting the shot for the first time.

The researchers concluded two things from these results. First, the immunity provided by the 4CMenB faded over time after the children received their initial four shots in infancy.

This fading has been seen with other meningococcal vaccines and some other bacterial diseases as well.

Second, those who already received the shots in infancy responded with better immunity to the booster than those who never received the shot before.

"If 4CMenB were introduced into routine vaccination schedules, assessment of the need for a booster dose would require data on the impact of these declining titers on vaccine effectiveness," the researchers wrote.

The 4CMenB was licensed for use in Europe in January this year but is not yet a part of the recommended immunization schedule in European countries.

The vaccine is not currently available in the US. Meningitis vaccines in the US protect against all meningitis bacterial strains (A, C, Y and W-135) except meningitis B strains.

The vaccine is one that the US Centers for Disease Control and Prevention (CDC) is studying.

"The meningitis B vaccine discussed in this study is currently not available in the US, but it is very promising that this is being studied," said Jessica McIntyre, MD, a family medicine physician at Loyola University Health System.

"Right now, it is important to get adolescents vaccinated with one of our available MCV4 vaccines," she said. The first dose at age 11-12, and a booster at age 16-18, cover the other five subtypes of meningitis-causing bacteria, Dr. McIntyre explained.

"In the future, the meningococcal B vaccine may be available and may become a recommended part of the infant or early childhood vaccination schedule," she said.

This study was published September 23 in the Canadian Medical Association Journal.

The research was funded by Novartis Vaccines and Diagnostics with additional support from the National Institute for Health Research Oxford Biomedical Research Centre at the University of Oxford in the UK. Novartis manufactures the 4CMenB vaccine.

Two authors, Snape and Andrew Pollard, have conducted clinical trials for the University of Oxford that were sponsored by Novartis Vaccines and Diagnostics, Pfizer, GlaxoSmithKline and Sanofi Pasteur MSD.

Snape and author Tessa John have received travel funds from Novartis, Pfizer and GlaxoSmithKline. Pollard chairs the European Medicines Agency's Scientific Advisory Group on Vaccines and is a member of the UK Department of Health’s Joint Committee on Vaccination and Immunization Meningococcal Sub-committee.

Three other study authors are Novartis employees. The other five authors reported no potential conflicts of interest.

Review Date: 
September 22, 2013