From the Journals

Study supports meningococcal B vaccine in children with rare diseases

Publish date: August 1, 2018
By
Randy Dotinga

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Keep eculizumab guidelines on antibiotic prophylaxis in mind

The Centers for Disease Control and Prevention reported an annual average of 792 cases of meningococcal disease and 98 deaths in the United States from 2006 to 2015 with serotype B isolates causing the highest numbers of cases. In a recent development, two vaccines against this strain have become available in the United States in the past 3 years for people aged 10-25 years. But officials don’t recommend their routine use, instead, guidelines suggest they be given to those at high risk only.

There’s a gap in knowledge because vaccine researchers didn’t include people with complement deficiency (either congenital or related to eculizumab), asplenia, or splenic dysfunction in studies that led to approval. Now, the new study offers reassuring findings regarding the latter two conditions, as bactericidal antibody responses were equal to those in healthy controls.

The findings regarding complement deficiency aren’t surprising, and suggest that vaccine strength in children with the condition only reached the levels in healthy children when an exogenous complement was added.

The study supports guidelines suggesting antibiotic prophylaxis in patients receiving eculizumab even if they already underwent meningococcal vaccination. It’s not clear if this approach also will be effective in those with congenital complement deficiencies (except for complement component 6 deficiency).

It is hoped that surveillance studies will show that use of serogroup B vaccines will prevent invasive meningococcal infections in these high-risk populations for which they are recommended.

Sheldon L. Kaplan, MD, is a pediatrician at Baylor College of Medicine and Texas Children’s Hospital, both in Houston. These comments are summarized from an editorial accompanying the article by Martinón-Torres et al. (Pediatrics. 2018 Aug 1. doi: 10.1542/peds.2018-0554).


 

FROM PEDIATRICS

A new study, the first of its kind, provided support for guidelines suggesting that the capsular meningococcal B vaccine be given to children with three rare conditions that boost infection risk.

©Micah Young/istockphoto.com
The 4CMenB vaccine’s strength appeared to be similar in healthy children and in those with asplenia and splenic dysfunction. It may be weaker in those with complement deficiency, but it was not clear whether that affected its effectiveness. The study authors recommended that children with this condition receive antibiotic prophylaxis in addition to the vaccine.

For children with terminal chain complement deficiencies or who are undergoing treatment with eculizumab, “it is important that these patients are identified, receive education about sepsis management plans, and are prescribed prophylactic antibiotics according to local guidelines, along with vaccination, to provide every chance for them to be protected against this deadly disease,” the researchers wrote in Pediatrics.

While some countries suggest that the vaccine be given to all healthy infants, U.S. guidelines advise that the vaccine be given to preteenagers, teenagers, and adults who are considered at special risk. These include those with terminal chain complement deficiencies, who are believed to be up to 10,000 times more likely than healthy children to develop invasive meningococcal disease, and those who take eculizumab (Soliris). The risk groups recommended for vaccinations also include those with asplenia and splenic dysfunction, although their excess risk, if any, is unknown.

The new study of the capsular group meningococcal B vaccine, led by Federico Martinón-Torres, PhD, of the Hospital Clinico Universitario de Santiago de Compostela, Spain, adds to previous research that confirmed the effectiveness of vaccinating complement-deficient patients with capsular group A, C, W, and Y meningococcal vaccines.

For the open-label, phase 3b study, researchers in Italy, Spain, Poland, and Russia gave two doses of the vaccine 2 months apart to 239 children aged 2-17 years with an average age of 10 years. Nearly all were white, and 45% were female.

A total of 40 children had complement deficiency, 112 had asplenia or splenic dysfunction, and 87 children in the control group also received the vaccine.

Following vaccination, the percentages of children with exogenous complement serum bactericidal activity titers greater than or equal to 1:5 to the four test strains were similar in the healthy children and those with asplenia/splenic dysfunction. “It is reasonable to expect that this vaccine will be as effective in children with asplenia or splenic deficiency as in children in the control category,” the researchers wrote.

However, these levels were lower in the complement-deficient children, particularly in those with terminal chain complement deficiency and those who took eculizumab.

The proportions of children with exogenous complement serum bactericidal activity titers greater than or equal to 1:5 against the four test strains were 87% (H44/76), 95% (5/99), 68% (NZ98/254), and 73% (M10713) in complement-deficient children, compared with 98%, 99%, 83%, and 99%, respectively, in the healthy controls.

“Ongoing surveillance for vaccine failures is required to determine the significance of the trend to reduced immune response in children with terminal chain complement deficiencies or undergoing treatment with eculizumab,” the researchers wrote.

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