Safety and recommendations for vaccinations of children with inborn errors of metabolism

Immunization coverage and timeliness of vaccination in young patients with inborn errors of metabolism: a French multicentric study

BACKGROUND

Inborn errors of metabolism (IEMs) are rare disorders that are heterogeneous in severity and clinical presentation. Patients with IEMs should receive the vaccination schedule recommended for the whole population, and specific vaccinations, such as the seasonal influenza vaccine, for the most vulnerable. The aim of this study was to evaluate vaccination coverage and timeliness in young patients with an IEM.

PATIENTS & METHODS

We conducted a retrospective multicentric (7 centers) study between February 2021 and May 2022 evaluating vaccination coverage and delays in French young patients with an IEM according to the yearly French vaccination schedules published since 2002. The results were analyzed considering patient health conditions as stable or at risk (defined as cardiorespiratory failure or by an IEM with a serious risk of metabolic crisis).

RESULTS

Two hundred seventy-five patients were enrolled in this study. Among them, only 164 (60%) were up-to-date with the standard French vaccination schedule, and 229 (83%) had received at least one vaccine from this schedule late. The rate of delayed vaccination was significantly greater in the at-risk group than in the stable group for the main primaries and first booster doses of the DTaP-IPV-Hib vaccine and for the first MMR injection. Finally, only 30 to 35% of at-risk patients were vaccinated against influenza during the three previous winters.

CONCLUSION

Young patients with an IEM had insufficient vaccination coverage with significant delays, exposing them to vaccine-preventable diseases, particularly at-risk patients with cardiorespiratory failure or a serious risk of metabolic crisis. Furthermore, only a few of the most vulnerable patients had received specific vaccinations, such as the influenza vaccine. Therefore, optimizing vaccination within the recommended schedule is crucial for this population of vulnerable children who have regular hospital follow-up.

Diminished measles immunity after paediatric liver transplantation-A retrospective, single-centre, cross-sectional analysis

Liver transplantation in childhood has an excellent long-term outcome, but is associated with a long-term risk of infection. Measles is a vaccine-preventable infection, with case series describing severe courses with graft rejection, mechanical ventilation and even death in liver transplant recipients. Since about 30% of liver transplanted children receive liver transplants in their first year of life, not all have reached the recommended age for live vaccinations. On the contrary, live vaccines are contraindicated after transplantation. In addition, vaccination response is poorer in individuals with liver disease compared to healthy children. This retrospective, single-centre, cross-sectional study examines measles immunity in paediatric liver transplant recipients before and after transplantation. Vaccination records of 239 patients, followed up at Hannover Medical School between January 2021 and December 2022 were analysed. Twenty eight children were excluded due to stem cell transplantation, regular immunoglobulin substitution or measles vaccination after transplantation. More than 55% of all 211 children analysed and 75% of all those vaccinated at least once are measles seropositive after transplantation-48% after one and 84% after two vaccinations-which is less than in healthy individuals. Interestingly, 26% of unvaccinated children also showed measles antibodies and about 5-15% of vaccinated patients who were seronegative at the time of transplantation were seropositive afterwards, both possibly through infection. In multivariable Cox proportional hazards regression, the number of vaccinations (HR 4.30 [95% CI 2.09-8.83], p<0.001), seropositivity before transplantation (HR 2.38 [95% CI 1.07-5.30], p = 0.034) and higher age at time of first vaccination (HR 11.5 [95% CI 6.92-19.1], p<0.001) are independently associated with measles immunity after transplantation. In contrast, older age at testing is inversely associated (HR 0.09 [95% CI 0.06-0.15], p<0.001), indicating a loss of immunity. Vaccination in the first year of life does not pose a risk of non-immunity. The underlying liver disease influences the level of measles titres of twice-vaccinated patients; those with acute liver failure being the lowest compared to children with metabolic disease. In summary, vaccine response is poorer in children with liver disease. Liver transplant candidates should be vaccinated before transplantation even if this is earlier in the first year of life. Checking measles IgG and re-vaccinating seronegative patients may help to achieve immunity after transplantation.

Clinical and biochemical footprints of inherited metabolic diseases. XIII. Respiratory manifestations

At any age, respiratory manifestations are a major cause of increased morbidity and mortality of inherited metabolic diseases (IMDs). Type and severity are extremely variable, this depending on the type of the underlying disorder. Symptoms and signs originating from upper or lower airways and/or thoracic wall and/or respiratory muscles involvement can occur either at presentation or in the late clinical course. Acute respiratory symptoms can trigger metabolic decompensation which, in turn, makes airway symptoms worse, creating a vicious circle. We have identified 181 IMDs associated with various types of respiratory symptoms which were classified into seven groups according to the type of clinical manifestations affecting the respiratory system: (i) respiratory failure, (ii) restrictive lung disease, (iii) interstitial lung disease, (iv) lower airway disease, (v) upper airway obstruction, (vi) apnea, and (vii) other. We also provided a list of investigations to be performed based on the respiratory phenotypes and indicated the therapeutic strategies currently available for IMD-associated airway disease. This represents the thirteenth issue in a series of educational summaries providing a comprehensive and updated list of metabolic differential diagnoses according to system involvement.

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.

Impact of the SARS-CoV-2 pandemic on the health of individuals with intoxication-type metabolic diseases-Data from the E-IMD consortium

The SARS-CoV-2 pandemic challenges healthcare systems worldwide. Within inherited metabolic disorders (IMDs) the vulnerable subgroup of intoxication-type IMDs such as organic acidurias (OA) and urea cycle disorders (UCD) show risk for infection-induced morbidity and mortality. This study (observation period February 2020 to December 2021) evaluates impact on medical health care as well as disease course and outcome of SARS-CoV-2 infections in patients with intoxication-type IMDs managed by participants of the European Registry and Network for intoxication type metabolic diseases Consortium (E-IMD). Survey's respondents managing 792 patients (n = 479 pediatric; n = 313 adult) with intoxication-type IMDs (n = 454 OA; n = 338 UCD) in 14 countries reported on 59 (OA: n = 36; UCD: n = 23), SARS-CoV-2 infections (7.4%). Medical services were increasingly requested (95%), mostly alleviated by remote technologies (86%). Problems with medical supply were scarce (5%). Regular follow-up visits were reduced in 41% (range 10%-50%). Most infected individuals (49/59; 83%) showed mild clinical symptoms, while 10 patients (17%; n = 6 OA including four transplanted MMA patients; n = 4 UCD) were hospitalized (metabolic decompensation in 30%). ICU treatment was not reported. Hospitalization rate did not differ for diagnosis or age group (p = 0.778). Survival rate was 100%. Full recovery was reported for 100% in outpatient care and 90% of hospitalized individuals. SARS-CoV-2 impacts health care of individuals with intoxication-type IMDs worldwide. Most infected individuals, however, showed mild symptoms and did not require hospitalization. SARS-CoV-2-induced metabolic decompensations were usually mild without increased risk for ICU treatment. Overall prognosis of infected individuals is very promising and IMD-specific or COVID-19-related complications have not been observed.

BNT162b2 COVID-19 vaccination elicited protective robust immune responses in pediatric patients with inborn errors of metabolism

Introduction

SARS-CoV-2 infection can lead to a life-threatening acute metabolic decompensation in children with inborn errors of metabolism (IEM), so vaccination is mandatory. However, IEMs can also impair innate or adaptive immunity, and the impact of these immune system alterations on immunogenicity and vaccine efficacy is still unknown. Here, we investigated humoral immune responses to the BNT162b2 mRNA COVID-19 vaccine and clinical outcomes in pediatric IEM patients.

Methods

Fifteen patients between 12-18 years of age with a confirmed diagnosis of IEM, and received BNT162b2 were enrolled to the study. Patients with an anti-SARS-CoV-2 IgG concentration >50 AU/mL before vaccination were defined as "COVID-19 recovered" whereas patients with undetectable anti-SARS-CoV-2 IgG concentration were defined as "COVID-19 naïve". Anti-SARS-CoV-2 Immunoglobulin G (IgG) and SARS-CoV-2 neutralizing antibody (nAb) titers were measured to assess humoral immune response.

Results

Anti-SARS-CoV-2 IgG titers and nAb IH% increased significantly after the first dose. The increase in antibody titers after first and second vaccination remained significant in COVID-19 naïve patients. Complete anti-SARS-CoV-2 IgG seropositivity and nAb IH% positivity was observed in all patients after the second dose. Vaccination appears to be clinically effective in IEM patients, as none of the patients had COVID-19 infection within six months of the last vaccination.

Discussion

Humoral immune response after two doses of BNT162b2 in pediatric IEM patients was adequate and the immune response was not different from that of healthy individuals.

Safety of COVID-19 vaccines in children with inborn errors of metabolism in terms of developing metabolic decompensation

AIM

There are no recommended guidelines or clinical studies on safety of COVID-19 vaccines in patients with inborn errors of metabolism (IEMs). Here, we aimed to examine the relationship between COVID-19 vaccination and metabolic outcome in paediatric IEM patients.

METHODS

Patients with IEM between the ages of 12 and 18 were enrolled. Term metabolic decompensation was defined as acute disruption in metabolic homeostasis due to vaccination. Clinical and biochemical markers were compared between pre- and post-vaccination periods.

RESULTS

Data from a total of 36 vaccination episodes in 18 patients were included. Thirteen patients had intoxication-type metabolic disorders including organic acidemia (OA), urea cycle disorders (UCDs), maple syrup urine disease (MSUD) and phenylketonuria (PKU); 4 patients had energy metabolism disorders including fatty acid metabolism disorders and LIPIN 1 deficiency; and 1 patient had glycogen storage disorder (GSD) type 5. Seventeen patients received BNT162b2, and 1 received CoronaVac because of an underlying long QT syndrome. Fatty acid metabolism disorders, LIPIN 1 deficiency and GSD type 5 were included in the same group named 'metabolic myopathies'. In two PKU patients, plasma phenylalanine level increased significantly within 24 h following the second dose of vaccination. None of the OA, UCD, MSUD and metabolic myopathy patients experienced acute metabolic attack and had emergency department admission due to metabolic decompensation within 1 month after vaccination.

CONCLUSIONS

COVID-19 vaccines did not cause acute metabolic decompensation in a cohort of 18 children with IEM.

COVID-19 Vaccine in Inherited Metabolic Disorders Patients: A Cross-Sectional Study on Rate of Acceptance, Safety Profile and Effect on Disease

BACKGROUND

Vaccines for COVID-19 have had a significant impact on the spread of COVID-19 infection, reducing the incidence and mortality of the infection in several countries. However, hesitancy toward this vaccine is a global health issue for the general population The Vaccine acceptance rate among patients affected with inherited metabolic disorders (IMD), as well as safety profile, has not been described.

METHODS

We conducted a cross-sectional study, based on a telephone survey, investigating the COVID-19 vaccination rate, the incidence and type of adverse effects (AEs), the reasons for vaccine refusal and the effects on the underlying disease in a cohort of IMD patients followed at a single center and invited directly to vaccination by specialistic team.

RESULTS

Seventy-four patients were included in the study, the median age was 23.4 years (min 12.1-max 61.7), 47% (n = 85) were females and 61% (107) were affected from impaired metabolism of phenylalanine. By October 2021, 94% (n = 163) of them had received at least one dose of the vaccine, which was, in 98% of cases, mRNA-based vaccine, given at the referral hospital in 65% of cases. Overall, 72% of patients with IMD reported AE to the vaccine: 60% after the first dose, 81% after the second. The highest rate of adverse events at the first dose was reported in patients with amino acids related disorders other than impaired phenylalanine metabolism (PKU/HPA) (88%). For the second dose, the PKU/HPA group reported the highest rate of AEs (89% of cases). There was no effect on the underlying disease or acute decompensation after the vaccine. Eleven patients (6%) were not vaccinated because they considered it dangerous.

CONCLUSION

Among individuals with IMD, the vaccination rate was high, the incidence and severity of AEs were comparable to those in the general population with no effects on the disease. Direct contact with the specialist medical team, has proven to reassure patients and effectively contrast hesitancy.

Immune Alterations in a Patient With Hyperornithinemia-Hyperammonemia-Homocitrullinuria Syndrome: A Case Report

The hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive inborn error of the urea cycle caused by mutations in the SLC25A15 gene. Besides the well-known metabolic complications, patients often present intercurrent infections associated with acute hyperammonemia and metabolic decompensation. However, it is currently unknown whether intercurrent infections are associated with immunological alterations besides the known metabolic imbalances. Herein, we describe the case of a 3-years-old girl affected by the HHH syndrome caused by two novel SLC25A15 gene mutations associated with immune phenotypic and functional alterations. She was admitted to the hospital with an episode of recurrent otitis, somnolence, confusion, and lethargy. Laboratory tests revealed severe hyperammonemia, elevated serum levels of liver transaminases, hemostasis alterations, hyperglutaminemia and strikingly increased orotic aciduria. Noteworthy, serum protein electrophoresis showed a reduction in the gamma globulin fraction. Direct sequencing of the SLC25A15 gene revealed two heterozygous non-conservative substitutions in the exon 5: c.649G>A (p.Gly217Arg) and c.706A>G (p.Arg236Gly). In silico analysis indicated that both mutations significantly impair protein structure and function and are consistent with the patient clinical status confirming the diagnosis of HHH syndrome. In addition, the immune analysis revealed reduced levels of serum IgG and striking phenotypic and functional alterations in the T and B cell immune compartments. Our study has identified two non-previously described mutations in the SLC25A15 gene underlying the HHH syndrome. Moreover, we are reporting for the first time functional and phenotypic immunologic alterations in this rare inborn error of metabolism that would render the patient immunocompromised and might be related to the high frequency of intercurrent infections observed in patients bearing urea cycle disorders. Our results point out the importance of a comprehensive analysis to gain further insights into the underlying pathophysiology of the disease that would allow better patient care and quality of life.