Safety and immunogenicity of subcutaneous hepatitis A vaccine in children with haemophilia

How does geographical diversity shape vaccine efficacy?

Vaccination is a cornerstone of public health, saving millions of lives each year by preventing a variety of infectious diseases. Yet, despite global vaccination efforts, emerging research highlights significant geographical disparities in vaccine efficacy and immunogenicity. These variations underscore the critical interplay between immunological factors and environmental, genetic, and nutritional elements across different populations. Our review article aimed to explore the multifactorial reasons behind geographical variations in vaccine efficacy. Also, this study has shown how important host factors like age, obesity, gender, and genetic diversity, especially within the major histocompatibility complex, are in determining how well a vaccine works. Nutritional status, namely deficiencies in micronutrients such as vitamins and zinc, and lifestyle factors including stress, sleep, alcohol consumption, and physical activity are also shown to have profound effects on vaccine-induced immunity. Importantly, our paper also brought to light the influence of microbial and ecological factors, such as the gut microbiome and environmental pollutants, on the immune system's response to vaccination. The findings emphasize the importance of tailoring vaccination strategies to accommodate the unique immunological landscapes shaped by geographical and societal factors. This tailored approach could enhance vaccine efficacy, reduce disparities in vaccine response, and ultimately contribute to the global fight against infectious diseases.

Safety and immunogenicity of BK-SE36 in a blinded, randomized, controlled, age de-escalating phase Ib clinical trial in Burkinabe children

Background

A blood-stage vaccine targeting the erythrocytic-stages of the malaria parasite Plasmodium falciparum could play a role to protect against clinical disease. Antibodies against the P. falciparum serine repeat antigen 5 (SE47 and SE36 domains) correlate well with the absence of clinical symptoms in sero-epidemiological studies. A previous phase Ib trial of the recombinant SE36 antigen formulated with aluminum hydroxyl gel (BK-SE36) was promising. This is the first time the vaccine candidate was evaluated in young children below 5 years using two vaccination routes.

Methods

Safety and immunogenicity of BK-SE36 was assessed in a double-blind, randomized, controlled, age de-escalating phase Ib trial. Fifty-four Burkinabe children in each age cohort, 25–60 or 12–24 months, were randomized in a 1:1:1 ratio to receive three doses of BK-SE36 either by intramuscular (BK IM) or subcutaneous (BK SC) route on Day 0, Week 4, and 26; or the control vaccine, Synflorix^®via IM route on Day 0, Week 26 (and physiological saline on Week 4). Safety data and samples for immunogenicity analyses were collected at various time-points.

Results

Of 108 subjects, 104 subjects (96.3%) (Cohort 1: 94.4%; Cohort 2: 98.1%) received all three scheduled vaccine doses. Local reactions, mostly mild or of moderate severity, occurred in 99 subjects (91.7%). The proportion of subjects that received three doses without experiencing Grade 3 adverse events was similar across BK-SE36 vaccines and control arms (Cohort 1: 100%, 89%, and 89%; and Cohort 2: 83%, 82%, and 83% for BK IM, BK SC, and control, respectively). BK-SE36 vaccine was immunogenic, inducing more than 2-fold change in antibody titers from pre-vaccination, with no difference between the two vaccination routes. Titers waned before the third dose but in both cohorts titers were boosted 6 months after the first vaccination. The younger cohort had 2-fold and 4-fold higher geometric mean titers compared to the 25- to 60-month-old cohort after 2 and 3 doses of BK-SE36, respectively.

Conclusion

BK-SE36 was well tolerated and immunogenic using either intramuscular or subcutaneous routes, with higher immune response in the younger cohort.

Clinical Trial Registration

https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=934, identifier PACTR201411000934120.

Safety of intramuscular COVID-19 vaccination in patients with haemophilia

Background

Guidelines recommend that patients with haemophilia should preferably receive vaccination subcutaneously. COVID‐19 and other vaccines, however, are only licenced for intramuscular application.

Aims

To assess the safety of intramuscular COVID‐19 vaccination in patients living with haemophilia.

Methods

Part A of this prospective observational study enrolled consecutive patients with haemophilia A (HA) and B (HB) of all ages and severities and assessed injection site bleeding and other complications within 30 days of vaccination. Part B enrolled patients providing informed consent for detailed data collection including medication and prophylaxis around the time of vaccination. Logistic regression was performed to assess potential risk factors for bleeding.

Results

Four hundred and sixty‐one patients were enrolled into part A. The primary endpoint injection site bleeding occurred in seven patients (1.5%, 95% confidence interval .7–3.1%). Comprehensive analysis of 214 patients (404 vaccinations, part B) revealed that 97% of patients with severe haemophilia had prophylaxis before vaccination, either as part of their routine prophylaxis or using additional doses. 56% and 30% of patients with moderate and mild haemophilia, respectively, received prophylaxis before vaccination. Among the seven bleeds recorded, three occurred when intramuscular vaccination was done without prophylaxis (odds ratio 12).

Conclusions

This is the first prospective study reporting on the safety of intramuscular vaccination in haemophilia. The rate of injection site bleeding was low in mild haemophilia, and in moderate and severe haemophilia if patients received factor prophylaxis.

Viral hepatitis in haemophilia: historical perspective and current management

The introduction of clotting factor concentrates has substantially improved the lives of people with clotting factor deficiencies. Unfortunately, the transmission of blood-borne viral infections through these plasma-derived products led to a huge epidemic of human immunodeficiency virus and viral hepatitis in people with haemophilia (PWH). In a significant proportion of PWH exposed to these viruses, the ensuing decades-long chronic infection resulted in excess morbidity and mortality. Fortunately, developments in the safety of blood products, as well as vaccination and highly effective antiviral treatments have improved the prospects of PWH. The present article reviews the background of the viral hepatitis epidemic in PWH, the natural history of hepatitis B and C infections and their long-term management.

Subcutaneous vaccine administration - an outmoded practice

Subcutaneous vaccine (SC) administration is an outmoded practice which complicates vaccine administration recommendations. Local adverse events following immunization (AEFIs) are a recognized determinant of vaccine hesitancy/refusal which can lead to an increased prevalence of vaccine-preventable disease.This extensive narrative review provides high-grade evidence that intramuscular (IM) administration of all vaccine types [adjuvanted, live virus and non-adjuvanted (inactivated whole cell, split cell and subunit)] significantly reduces the likelihood of local adverse events. This, combined with moderate grade evidence that IM injection generates significantly greater immune response compared with SC injection, allows a strong recommendation to be made for the IM injection of all vaccines except BCG and Rotavirus.This will simplify vaccination practice, minimize the inadvertent misadministration of vaccines and potentially improve public trust in vaccination.

Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020

HEPATITIS A IS A VACCINE-PREVENTABLE, COMMUNICABLE DISEASE OF THE LIVER CAUSED BY THE HEPATITIS A VIRUS (HAV). THE INFECTION IS TRANSMITTED VIA THE FECAL-ORAL ROUTE, USUALLY FROM DIRECT PERSON-TO-PERSON CONTACT OR CONSUMPTION OF CONTAMINATED FOOD OR WATER. HEPATITIS A IS AN ACUTE, SELF-LIMITED DISEASE THAT DOES NOT RESULT IN CHRONIC INFECTION. HAV ANTIBODIES (IMMUNOGLOBULIN G [IGG] ANTI-HAV) PRODUCED IN RESPONSE TO HAV INFECTION PERSIST FOR LIFE AND PROTECT AGAINST REINFECTION; IGG ANTI-HAV PRODUCED AFTER VACCINATION CONFER LONG-TERM IMMUNITY. THIS REPORT SUPPLANTS AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) REGARDING THE PREVENTION OF HAV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS ROUTINE VACCINATION OF CHILDREN AGED 12-23 MONTHS AND CATCH-UP VACCINATION FOR CHILDREN AND ADOLESCENTS AGED 2-18 YEARS WHO HAVE NOT PREVIOUSLY RECEIVED HEPATITIS A (HEPA) VACCINE AT ANY AGE. ACIP RECOMMENDS HEPA VACCINATION FOR ADULTS AT RISK FOR HAV INFECTION OR SEVERE DISEASE FROM HAV INFECTION AND FOR ADULTS REQUESTING PROTECTION AGAINST HAV WITHOUT ACKNOWLEDGMENT OF A RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE GUIDANCE FOR VACCINATION BEFORE TRAVEL, FOR POSTEXPOSURE PROPHYLAXIS, IN SETTINGS PROVIDING SERVICES TO ADULTS, AND DURING OUTBREAKS.

Immunogenicity, long term protection and safety of subcutaneous administration of hepatitis A vaccine in patients with hemophilia and other bleeding disorders: A randomized study

Hepatitis A vaccine is recommended for all individuals with hemophilia, although patients with bleeding disorders should avoid intramuscular (IM) injections. To date, only few studies showed subcutaneous (SC) route immunogenicity is comparable with the IM route. Therefore, this randomized study compared immunogenicity, long term protection and safety of hepatitis A vaccine administered by SC route with the IM route in 78 children and adults with hemophilia and other bleeding disorders. Thirty-eight patients had serology performed after first vaccine dose, determining seroconversion rates of 83.3% and 90.0% for the SC and the IM group, respectively (p = 0.5). Median IgG CO/OD value for the SC group was almost the double compared with the IM group (4.4 vs 2.6, p = 0.2). After second vaccine dose, seroconversion rates for the SC group was 97.5% and for the IM group was 97.4% (p = 1.0). Of the two patients who did not have seroconversion, interval between vaccine dose and serology was only one and two days for the SC and the IM group, respectively and in the following routine antibody dosage they presented seroconversion (100% for both groups). Median IgG CO/OD value for the SC group was greater than the IM group (72.5 vs. 58.0, p = 0.2). In a median of nine years after second vaccine dose, median IgG S/CO value for the SC group was slightly greater than the IM group (7.6 vs. 7.4, p = 0.8). There were no serious adverse events in both groups. Five (12.5%) patients of the SC group and seven (18.4%) of the IM group presented adverse events (p = 0.5). Twice as many patients of the IM group had clotting factor concentrates need for adverse events (15.8% vs. 7.5%, p = 0.3). Therefore, hepatitis A vaccine administered subcutaneously is as immunogenic, long term protective and even safer than the intramuscular route.

'Do not Do' Recommendations in Hemophilia

BACKGROUND

It is important to discard those practices that do not add value. As a result, several initiatives have emerged. All of them try to improve patient safety and the use of health resources.

PURPOSE

To present a compendium of "do not do recommendations" in the context of hemophilia.

METHODS

A review of the literature and current clinical guidelines has been made, based on the best evidence available to date.

RESULTS

The following 13 recommendations stand out: 1) Do not delay the administration of factor after trauma; 2) do not use fresh frozen plasma or cryoprecipitate; 3) do not use desmopressin in case of hematuria; 4) do not change the product in the first 50 prophylaxis exposures; 5) do not interrupt immunotolerance; 6) do not administer aspirin or NSAIDs; 7) do not administer intramuscular injections; 8) do not do routine radiographs of the joint in case of acute hemarthrosis; 9) Do not apply closed casts for fractures; 10) do not discourage the performance of physical activities; 11) do not deny surgery to a patient with an inhibitor; 12) do not perform instrumental deliveries in fetuses with hemophilia; 13) do not use factor IX (FIX) in patients with hemophilia B with inhibitor and a history of anaphylaxis after administration of FIX.

CONCLUSION

The information mentioned previously can be useful in the management of hemophilia, from different levels of care. As far as we know, this is the first initiative of this type regarding hemophilia.

Hepatitis A immunisation in persons not previously exposed to hepatitis A

This review is withdrawn because it is outdated. A new review is to be published by the end of 2019.

Subcutaneous diphtheria and tetanus vaccines in children with haemophilia: A pilot study and review of the literature

INTRODUCTION

Subcutaneous (SQ) vaccination has emerged as standard of care in children with severe bleeding disorders to reduce unnecessary factor exposure and avoid provoking an intramuscular bleed, but little is known about comparative immunogenicity to intramuscular (IM) vaccination.

AIM

To confirm immunogenicity of Diphtheria Tetanus acellular Pertussis (DTaP) vaccines administered SQ to individuals <6 years old with haemophilia.

METHODS

We performed a retrospective and prospective pilot study of tetanus and diphtheria antibody titres among patients evaluated at our Haemophilia Treatment Centre between 2015-2016. Children with haemophilia who had received three to four doses of DTaP containing vaccine administered SQ were eligible.

RESULTS

Eight children met inclusion criteria. The mean age at the time of diphtheria and tetanus antibody testing was 21.1±17.8 months. All children who received SQ diphtheria and tetanus developed a positive antibody titre to both antigens. There was no statistically significant difference in distribution of titre values. The average time between the last dose of vaccine and antibody testing was 6.6±3.9 months among SQ vaccinated subjects. Minor injection site reactions were common with SQ vaccines.

CONCLUSION

SQ administration of diphtheria and tetanus vaccination appears to be immunogenic in a pilot study of Haemophilia patients and supports this practice as the standard of care for this population.

Hepatitis B vaccination is effective by subcutaneous route in children with bleeding disorders: a universal data collection database analysis

Subcutaneous (SQ) vs. intramuscular (IM) vaccination may cause fewer injection site complications in children with bleeding disorders, but little is known about comparative immunogenicity. To compare immunogenicity of hepatitis B virus (HBV) vaccination administered SQ or IM to individuals <2 years old with bleeding disorders, we performed a retrospective analysis of HBV surface antibody titres among patients enrolled in the universal data collection database who had received three doses of HBV vaccine solely by one route (SQ or IM). Data reviewed were from an initial visit before 24 months of age, until time of hepatitis antibody titre testing. The SQ and IM study groups did not differ in demographics, haemophilia type or severity or bleeding history. The mean age at the time of HBV surface antibody (anti-HBs) testing was 56.9 ± 20.3 months. Eighty-five of 92 subjects (92.4%) who received vaccine SQ developed a positive antibody titre (>12 IU/L), compared to 101/114 (88.6%) who received IM (P = 0.30). There was no statistically significant difference in distribution of titre values. The average age of the subjects at time of testing was 53 ± 20 months in the SQ group vs. 60 ± 20 months in the IM group (P = 0.02). The average time between the last dose of vaccine and anti-HBs testing was 47.6 ± 18.5 months among SQ vaccinated subjects vs. 51.6 ± 20.5 months in the IM group (P = 0.2). Immunogenicity to hepatitis B vaccination by the SQ and IM routes is similar.

Hepatitis A immunisation in persons not previously exposed to hepatitis A

BACKGROUND

In many parts of the world, hepatitis A infection represents a significant cause of morbidity and socio-economic loss. Whilst hepatitis A vaccines have the potential to prevent disease, the degree of protection afforded against clinical outcomes and within different populations remains uncertain. There are two types of hepatitis A virus (HAV) vaccine, inactivated and live attenuated. It is important to determine the efficacy and safety for both vaccine types.

OBJECTIVES

To determine the clinical protective efficacy, sero-protective efficacy, and safety and harms of hepatitis A vaccination in persons not previously exposed to hepatitis A.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and China National Knowledge Infrastructure (CNKI) up to November 2011.

SELECTION CRITERIA

Randomised clinical trials comparing HAV vaccine with placebo, no intervention, or appropriate control vaccines in participants of all ages.

DATA COLLECTION AND ANALYSIS

Data extraction and risk of bias assessment were undertaken by two authors and verified by a third author. Where required, authors contacted investigators to obtain missing data. The primary outcome was the occurrence of clinically apparent hepatitis A (infectious hepatitis). The secondary outcomes were lack of sero-protective anti-HAV immunoglobulin G (IgG), and number and types of adverse events. Results were presented as relative risks (RR) with 95% confidence intervals (CI). Dichotomous outcomes were reported as risk ratio (RR) with 95% confidence interval (CI), using intention-to-treat analysis. We conducted assessment of risk of bias to evaluate the risk of systematic errors (bias) and trial sequential analyses to estimate the risk of random errors (the play of chance).

MAIN RESULTS

We included a total of 11 clinical studies, of which only three were considered to have low risk of bias; two were quasi-randomised studies in which we only addressed harms. Nine randomised trials with 732,380 participants addressed the primary outcome of clinically confirmed hepatitis A. Of these, four trials assessed the inactivated hepatitis A vaccine (41,690 participants) and five trials assessed the live attenuated hepatitis A vaccine (690,690 participants). In the three randomised trials with low risk of bias (all assessing inactivated vaccine), clinically apparent hepatitis A occurred in 9/20,684 (0.04%) versus 92/20,746 (0.44%) participants in the HAV vaccine and control groups respectively (RR 0.09, 95% CI 0.03 to 0.30). In all nine randomised trials, clinically apparent hepatitis A occurred in 31/375,726 (0.01%) versus 505/356,654 (0.18%) participants in the HAV vaccine and control groups respectively (RR 0.09, 95% CI 0.05 to 0.17). These results were supported by trial sequential analyses. Subgroup analyses confirmed the clinical effectiveness of both inactivated hepatitis A vaccines (RR 0.09, 95% CI 0.03 to 0.30) and live attenuated hepatitis A vaccines (RR 0.07, 95% CI 0.03 to 0.17) on clinically confirmed hepatitis A. Inactivated hepatitis A vaccines had a significant effect on reducing the lack of sero-protection (less than 20 mIU/L) (RR 0.01, 95% CI 0.00 to 0.03). No trial reported on a sero-protective threshold less than 10 mIU/L. The risk of both non-serious local and systemic adverse events was comparable to placebo for the inactivated HAV vaccines. There were insufficient data to draw conclusions on adverse events for the live attenuated HAV vaccine.

AUTHORS' CONCLUSIONS

Hepatitis A vaccines are effective for pre-exposure prophylaxis of hepatitis A in susceptible individuals. This review demonstrated significant protection for at least two years with the inactivated HAV vaccine and at least five years with the live attenuated HAV vaccine. There was evidence to support the safety of the inactivated hepatitis A vaccine. More high quality evidence is required to determine the safety of live attenuated vaccines.

Prevention of hepatitis A by vaccination

Inactivated hepatitis A vaccines have been available for more than a decade. Characteristics of the vaccines, comparative data among different formulations and the possibility of combination and association with other vaccines are reviewed in this article. Hepatitis A vaccines show high immunogenicity with different schedules and associations, induce long-term protection irrespective of timing of booster dose, and present an excellent safety profile. Pre-exposure efficacy has been demonstrated in large trials and postexposure protection has been described in family contacts of acute cases. The recommendations for the use of hepatitis A vaccines for immunisation campaigns and for targeted groups, such as travellers and people at risk for occupational and iatrogenic exposure or lifestyle behaviours, are discussed. Aspects related to economic analysis of vaccination strategies are also considered.

Adverse events and vaccination-the lack of power and predictability of infrequent events in pre-licensure study

The recent setback in the development of a safe and effective rotavirus vaccine illustrates an important problem regarding prelicensure testing and its ability to identify rare vaccine-related adverse effects. It is our contention that the possibility of a rare but serious vaccine adverse effect is difficult to detect in prelicensure testing. In this paper, we review the history regarding the testing and eventual studies that led to the permanent withdrawal of that vaccine. The post-licensure discovery of a serious adverse event associated with the rotavirus vaccine is not unique among vaccines, but represents a recurrent phenomenon that in fact is mathematically predictable. Prelicensure studies examine thousands of subjects and not hundreds of thousands. A sample size of 10,000 subjects may provide excellent estimates of efficacy, but cannot provide an adequate denominator to rule out rare adverse events. It lacks the power. Just as with the rotavirus vaccine, only after hundreds of thousands of doses of vaccines are distributed, will such rare events appear often enough to permit detection. For that reason, we must depend upon the modern post-licensure surveillance programs that we already have in place.

New-generation recombinant factor concentrates: bridge to gene therapy

Despite our best efforts to deceive the immune system, outwit pathogens, and improve upon the design of nature, there continues to be a need to improve the margin of safety of treatment for those with bleeding disorders. The current approach includes: (1) recombinant factor concentrates free of added proteins; (2) 'designer' factor molecules that enhance function and reduce immunogenicity; and (3) modulation of the immune system to suppress immune response in those who develop inhibitors. The hope is that through advances in our understanding of the coagulation and immune systems, treatment of haemophilia in the new millennium will be safer and less immunogenic. Currently available recombinant clotting factor concentrates include those produced: (1) with pasteurized human serum albumin in the cell culture medium as a stabilizer; (2) with bovine serum proteins in the cell culture medium; and (3) free of plasma derivatives. To the extent that current recombinant clotting factor concentrates contain even trace amounts of human or animal protein, there is continuing potential for transmission of nonenveloped viruses, including hepatitis A and parvovirus, and the theoretical potential for transmission of relatively unknown agents, such as prions (Creutzfeldt-Jakob disease or its variant). Second-generation recombinant factor concentrates that do not use human albumin as a stabilizer are currently in clinical trials, and third-generation recombinant factor concentrates currently in development take advantage of new strategies to achieve a 'protein-free' cell culture, purification, and final formulation. It is likely that improvement in safety and reduction in immunogenicity will require modification not only of antigenic structure but also of the immune response to coagulation proteins.