Immunization status and hospitalization for vaccine-preventable and non-vaccine-preventable infections in liver-transplanted children

Safety and Efficacy of a Third Dose of the BNT162b2 Vaccine in Liver-Transplanted and Healthy Adolescents

Objectives

According to our previous study, the 2-dose-BNT162b2 vaccination is less effective against the Omicron variant. This study aimed to assess the safety and efficacy of a 3-dose-BNT162b2 vaccination in liver-transplanted (LT) and healthy adolescents.

Methods

LT and healthy adolescents who met the inclusion criteria received a third dose of the BNT162b2 vaccine (30 µg). Antireceptor-binding domain immunoglobulin and T-cell-specific responses to severe acute respiratory syndrome coronavirus 2 spike peptides were assessed 3 months before the third dose (Visit -1) and 0 (Visit 0), 1 (Visit 1), and 2 months (Visit 2) after the third dose. Antinucleocapsid immunoglobulin and neutralizing antibodies were assessed at Visits 0 and 1. Adverse events (AEs) were monitored.

Results

Eleven LT and 14 healthy adolescents aged 14.64 (13.2, 15.7) years (44.2% male) had antireceptor-binding domain immunoglobulin geometric mean titers of 1412.47 (95% confidence interval [CI], 948.18-2041.11) and 1235.79 (95% CI, 901.07-1705.73) U/mL at Visit -1 but increased to 38 587.76 (95% CI, 24 628.03-60 460.18) and 29 222.38 (95% CI, 16 291.72-52 401.03) U/mL (P < 0.05) at Visit 1, respectively. This was consistent with neutralizing antibodies (42.29% and 95.37% vs 44.65% and 91.68%, P < 0.001) and interferon-γ-secreting cells in LT and healthy adolescents at Visit 0 versus Visit 1, respectively. For serious AEs, an LT girl with autoimmune overlap syndrome died 5 months postvaccination from acute liver failure.

Conclusions

In both LT and healthy adolescents, humoral and cellular immune responses were high after the 3-dose-BNT162b2 vaccination. However, serious AEs were suspected in LT adolescents with autoimmune diseases.

Parental perceptions, attitudes, and beliefs regarding vaccination of children aged 0-5 years: A qualitative study of hill-tribe communities, Thailand

The widespread availability and use of vaccines have tremendously reduced morbidity and deaths related to infectious diseases globally. However, in hill-tribe communities in Northern Thailand, vaccination rates remain low, and there is limited literature on parental perceptions, attitudes, and beliefs about vaccination for children under five years of age. We conducted a qualitative study employing semi-structured interviews to understand parents' perceptions, attitudes, and beliefs about vaccinations. A purposive sample was used to recruit participants. Data were analyzed using thematic analysis. 74 hill-tribe parents (14 Akha, 11 Hmong, 12 Lahu, 13 Lisu, 12 Karen, and 12 Yao) were interviewed. Four themes emerged from the interviews: 1) traditional beliefs, and practices 2) traumatic experiences, 3) lack of information and effective communication, and 4) trust and support from the community. Findings highlight that it is crucial to build trust by providing knowledge, appropriate information, and advice about vaccinations in order to improve vaccine coverage in children under five years of age in the hill-tribe context.

Vaccine-Preventable Infections Among Solid Organ Transplant Recipients in Switzerland

Importance

Vaccine responses are decreased in solid organ transplant (SOT) recipients, and given the complexity of implementation, vaccination programs may be suboptimal. The actual burden of vaccine-preventable infections (VPIs) among SOT recipients remains unclear.

Objectives

To assess the incidence rate of VPIs among SOT recipients and to evaluate whether SOT recipients are at increased risk for specific VPIs compared with the general population.

Design, Setting, and Participants

This nationwide cohort study used data from the Swiss Transplant Cohort Study on VPIs in individuals who underwent SOT from May 2008 to June 2019 (follow-up until December 2019) and data from the Swiss Federal Office of Public Health on notifiable VPIs in the general population in the same period. Data were analyzed from January 2021 to June 2022.

Exposures

Solid organ transplant.

Main Outcomes and Measures

The main outcomes were the incidence rate of the following VPIs in SOT recipients: hepatitis A and B, diphtheria, Haemophilus influenzae infection, influenza, measles, mumps, pertussis, pneumococcal disease, poliomyelitis, meningococcal disease, rubella, tetanus, tick-borne encephalitis, and varicella zoster virus infection. Age-adjusted standardized incidence ratios were used to assess whether VPIs occurred more frequently in SOT recipients compared with the general population. For SOT recipients, factors associated with occurrence of VPIs were explored and the associated morbidity and mortality assessed.

Results

Of 4967 SOT recipients enrolled (median age, 54 years [IQR, 42-62 years]; 3191 [64.2%] male), 593 (11.9%) experienced at least 1 VPI. The overall VPI incidence rate was higher in the population that underwent SOT (30.57 per 1000 person-years [PY]; 95% CI, 28.24-33.10 per 1000 PY) compared with the general population (0.71 per 1000 PY). The standardized age-adjusted incidence ratio for notifiable VPIs in SOT recipients was higher compared with the general population (27.84; 95% CI, 25.00-31.00). In SOT recipients, influenza and varicella zoster virus infection accounted for most VPI episodes (16.55 per 1000 PY [95% CI, 14.85-18.46 per 1000 PY] and 12.83 per 1000 PY [95% CI, 11.40-14.44 per 1000 PY], respectively). A total of 198 of 575 VPI episodes in the population that underwent SOT (34.4%) led to hospital admission, and the occurrence of a VPI was associated with an increased risk for death and/or graft loss (hazard ratio, 2.44; 95% CI, 1.50-3.99; P = .002). In multivariable analysis, age 65 years or older at the time of transplant (incidence rate ratio [IRR], 1.29; 95% CI, 1.02-1.62) and receipt of a lung (IRR, 1.77; 95% CI, 1.38-2.26) or a heart (IRR, 1.40; 95% CI, 1.05-1.88) transplant were associated with an increased risk of VPI occurrence.

Conclusions and Relevance

In this study, 11.9% of SOT recipients experienced VPIs, and the incidence rate was higher than in the general population. There was significant morbidity and mortality associated with these infections in the population that underwent SOT, which highlights the need for optimizing immunization strategies.

[Vaccination coverage, beliefs, and attitudes in transplanted children and adolescents: a mixed-methods systematic review.]

OBJECTIVE

Vaccine-preventable infectious diseases are a cause of morbidity and mortality in transplanted children. The main objective of this study was to synthesize the available evidence of vaccination coverage in children and adolescents who are candidates or transplant recipients and to analyze beliefs, attitudes, and experiences about vaccination.

METHODS

A mixed-methods systematic review was performed (Open Science Framework registration: https://osf.io/auqn3/). Searches were conducted in PubMed/MEDLINE, EMBASE, IBECS and LILACS (from January 2000 to August 2021) and in gray literature. Quantitative and qualitative studies reported information on coverage, beliefs, attitudes and/or experiences about recommended vaccines in children who are candidates or recipients of solid organ or hematopoietic progenitor transplantation. Quality assessment was undertaken using Mixed Methods Appraisal Tool (MMAT). A narrative synthesis of the studies was carried out.

RESULTS

A total of thirty-two studies in thirty-five publications were included. The most studied interventions were vaccines against measles (n=21; 66%) and hepatitis B (n=20; 62%). Vaccination rates showed a high variability for the most represented vaccines (specifically, 2%-100% for measles, 0.4%-100% for hepatitis B, diphtheria-tetanus-pertussis and rubella), with coverages lower than 90% in at least 70% of the studies. The lowest rates were reported in post-transplantation and hematopoietic stem cell transplantation. Only one qualitative study was identified reporting information on beliefs and/or attitudes, although nine quantitative studies explored cognitive aspects.

CONCLUSIONS

This review shows a high variability in vaccination coverage in children and adolescents who are transplant candidates or recipients, with rates lower than those recommended. Further studies would be needed to identify beliefs and attitudes about immunization in this context.

Eliminating viral hepatitis in children after liver transplants: How to reach the goal by 2030

Viral hepatitis infections are a great burden in children who have received liver transplant. Hepatotropic viruses can cause liver inflammation that can develop into liver graft fibrosis and cirrhosis over the long term. Immunological reactions due to viral hepatitis infections are associated with or can mimic graft rejection, rendering the condition difficult to manage. Prevention strategies using vaccinations are agreeable to patients, safe, cost-effective and practical. Hence, strategies to eliminate viral hepatitis A and B focus mainly on immunization programmes for children who have received a liver transplant. Although a vaccine has been developed to prevent hepatitis C and E viruses, its use is not licensed worldwide. Consequently, eliminating hepatitis C and E viruses mainly involves early detection in children with suspected cases and effective treatment with antiviral therapy. Good hygiene and sanitation are also important to prevent hepatitis A and E infections. Donor blood products and liver grafts should be screened for hepatitis B, C and E in children who are undergoing liver transplantation. Future research on early detection of viral hepatitis infections should include molecular techniques for detecting hepatitis B and E. Moreover, novel antiviral drugs for eradicating viral hepatitis that are highly effective and safe are needed for children who have undergone liver transplantation.