Should children with inherited metabolic disorders receive varicella vaccination?

Vaccination strategies for people living with inborn errors of metabolism in Brazil

OBJECTIVE

Through a literature review, make recommendations regarding immunizations in people living with Inborn Error of Metabolism (IEM) in Brazil, assess the possible impact on metabolic decompensations after immunization, and if this specific population may have an impaired immune response to vaccines.

SOURCE OF DATA

The MeSH Terms vaccination OR vaccine OR immunization associated with the term inborn error of metabolism AND recommendation were used in combination with search databases. Only articles published after 1990, in the languages English, Spanish, French or Portuguese, human-related were included.

SYNTHESIS OF DATA

A total of 44 articles were included to make the following recommendations. Individuals with IEMs need to be up to date with their immunizations. Regarding which vaccines should be offered, children and adults should follow the routine immunization schedules locally available, including the COVID-19 vaccines. The only exception is the rotavirus vaccine for hereditary fructose intolerance. The benefit of immunization outweighs the very low risk of metabolic decompensation. Since not all patients will have an adequate immune response, measuring antibody conversion and titers is recommended CONCLUSIONS: All patients should receive age-appropriate immunizations in their respective schedules without delays. The only situation when vaccination may be contraindicated is with oral rotavirus vaccine in hereditary fructose intolerance. Monitoring the levels of antibodies should be done to detect any immune dysfunction or the necessity for boosters. A personalized immunization schedule is ideal for patients with IEMs. The reference organizations could improve their recommendations to address all IEMs, not only some of them.

Mitochondrial respiration restricts Listeria monocytogenes infection by slowing down host cell receptor recycling

Mutations in mitochondrial genes impairing energy production cause mitochondrial diseases (MDs), and clinical studies have shown that MD patients are prone to bacterial infections. However, the relationship between mitochondrial (dys)function and infection remains largely unexplored, especially in epithelial cells, the first barrier to many pathogens. Here, we generate an epithelial cell model for one of the most common mitochondrial diseases, Leigh syndrome, by deleting surfeit locus protein 1 (SURF1), an assembly factor for respiratory chain complex IV. We use this genetic model and a complementary, nutrient-based approach to modulate mitochondrial respiration rates and show that impaired mitochondrial respiration favors entry of the human pathogen Listeria monocytogenes, a well-established bacterial infection model. Reversely, enhanced mitochondrial energy metabolism decreases infection efficiency. We further demonstrate that endocytic recycling is reduced in mitochondrial respiration-dependent cells, dampening L. monocytogenes infection by slowing the recycling of its host cell receptor c-Met, highlighting a previously undescribed role of mitochondrial respiration during infection.

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Enhanced mitochondrial respiration decreases L. monocytogenes infection

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Bacterial entry is affected by the host cell metabolism

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Mitochondrial respiration restricts host cell receptor recycling and thus infection

Preliminary data on immunogenicity, safety and tolerability of trivalent inactivated influenza vaccine in children with inborn errors of metabolism at risk of decompensation

In order to evaluate the immunogenicity, safety and tolerability of influenza vaccination in children with inborn errors of metabolism (IEMs), we enrolled 20 patients with IEMs at risk of decompensation (14 males; mean age±SD, 8.5±3.9years) and 20 healthy age- and gender-matched controls. Four weeks after vaccination, seroconversion rates were 75-85% and seroprotection rates 85-95%, with high geometric mean titers (GMTs) of all three influenza antigen strains in both groups. Three months after vaccination, most of the subjects remained seroconverted with high seroprotection rates and high GMTs for all the three influenza strains. Safety and tolerability were also very good, with no differences between the groups.

Evaluation of immunization rates and safety among children with inborn errors of metabolism

BACKGROUND

Children with inherited metabolic disorders are a potential high-risk group for vaccine-preventable diseases, yet information regarding immunization rates and vaccine safety within this population is limited.

METHODS

Using Northern California Kaiser Permanente's electronic medical record, we identified children with inborn errors of metabolism from 1990 to 2007. We assessed immunization rates among infants with inborn errors of metabolism born at Northern California Kaiser Permanente matched to healthy infants (1 to 20), comparing both vaccines received by 2 years of age and age at vaccination. We assessed postvaccination adverse events among children up to 18 years old with inborn errors of metabolism, separately comparing emergency-department visits and hospitalizations during postvaccine days 0 to 30 (primary) and days 0 to 14 (secondary).

RESULTS

Comparing infants with inborn errors of metabolism (n = 77) versus matched control subjects (n = 1540), similar proportions were up to date for vaccines at 2 years of age, and there was no evidence of delay in receipt of recommended vaccines during the first year. Vaccination of children with inborn errors of metabolism (n = 271) was not associated with any significant increase in emergency-department visits or hospitalizations during the 30 days after vaccination. Secondary analyses suggested that there may be increased rates of hospitalizations 2 weeks after vaccination for the sickest 1- to 4-year-old children.

CONCLUSIONS

Children with inborn errors of metabolism at Northern California Kaiser Permanente received vaccines on the same immunization schedule as healthy infants. Immunization was not associated with increased risk for serious adverse events during the month after vaccination, providing overall reassurance that routine vaccination of children with inborn errors of metabolism does not result in adverse effects.

Vaccines are not associated with metabolic events in children with urea cycle disorders

BACKGROUND

Despite the success of childhood immunizations in prevention of infectious diseases, questions remain about the safety of vaccines in medically fragile children with inborn errors of metabolism such as urea cycle disorders (UCDs). Patients with UCDs are subject to hyperammonemic episodes (HAEs) after infection, fever, or other stressors.

OBJECTIVE

We sought to assess the risk of HAEs that required urgent care or hospitalization after routine vaccinations in pediatric patients with underlying UCDs.

METHODS

This was a retrospective investigation of vaccine safety in children with UCDs within the longitudinal Rare Diseases Clinical Research Consortium for UCD. Postvaccination exposure periods were defined as 7 or 21 days after any immunization. The association of vaccines and HAEs was modeled by using conditional Poisson regression, adjusting for age, and using a self-controlled case series method including all patients with ≥1 HAE and with any vaccine exposure.

RESULTS

The study enrolled 169 children younger than 18 years. Of these children, 74 had records of at least 1 HAE and at least 1 vaccination. With adjustment for age, there was no increase in relative incidence of HAEs in either the 7-day (1.31 [95% confidence interval (CI): 0.80-2.13]) or 21-day (1.05 [95% CI: 0.74-1.47]) exposure period after vaccination compared with HAEs outside of the vaccination periods. No vaccine type was associated with significantly more HAEs.

CONCLUSIONS

We found no statistically significant association between childhood immunizations and HAEs in children with UCDs. The results support the safety of immunization in this medically vulnerable population.