Vaccination in patients with haemophilia-Results from an online survey among haemophilia treatment centres in Germany

Present status of scheduled vaccinations and vaccination-related bleeding in Chinese children with haemophilia

AIM

Many countries have detailed recommendations for haemophilia patients to reduce the risk of vaccination-related bleeding. However, data from developing countries are lacking. We investigated scheduled vaccinations and vaccination-related bleeding complications in Chinese children with haemophilia and analysed issues related to vaccinations.

METHODS

Children with haemophilia in the PUMCH Haemophilia Treatment Centre were contacted via telephone. We distributed a vaccination questionnaire to their parents. The severity of haemophilia, coagulation factor infusions before vaccination, injection mode, and vaccination-related complications were analysed.

RESULTS

A total of 440 valid questionnaires were received from 27 of 34 provinces in China. 31.3% (138/440) of the children with haemophilia did not receive all of their vaccinations. Among the children who received vaccinations, 48.1% (197/409) experienced bleeding complications. In patients with severe haemophilia, those on regular prophylaxis had a lower incidence of local hematoma compared to those on intermittent or no prophylaxis (14.3% vs. 26.5% vs. 39.7%, P < 0.05). The incidence of local hematomas was lower by subcutaneous (SQ) injections than by intramuscular injections (24.6% vs. 35.3%, P < 0.05).

CONCLUSION

The vaccination rate is quite insufficient in Chinese children with haemophilia. Missed vaccinations are related to vaccination-related bleeding complications. Prophylaxis before vaccination and SQ injections would help reduce bleeding complications.

Catch-up vaccination and enhanced immunization against hepatitis B, hepatitis A, measles, mumps, rubella and varicella in children with idiopathic thrombocytopenic purpura

BACKGROUND

Limited data exist about the vaccination of children with idiopathic thrombocytopenic purpura (ITP) against vaccine preventable diseases. This study identified the vaccination status of children with ITP against hepatitis A, hepatitis B, measles, mumps, rubella and varicella, completed the immunization of children with inadequate immunization, re-evaluated post-vaccination antibody titers and identified probable vaccination-related complications.

PATIENTS AND METHODS

All of 46 children had chronic ITP were included. Seroconversion of hepatitis A, hepatitis B, varicella, measles, rubella and mumps vaccines was screened. All children with seronegative antibodies against vaccine preventable disease were given a vaccination appointment. Antibody levels were re-measured during a period ranging from 1 to 6 months. Potential complications were detected.

RESULTS

There were 46 children with a mean age of 12.25 years. All children had chronic ITP and received intravenous immunoglobulin at least once previously. Considering the vaccination status, 50% (23 children) had vaccinations appropriate for their age, 47.8% (22 children) did not know their vaccination status and 2.2% (1 patient) did not have vaccinations. Seven children (15.2%) were seropositive for all antibody types and the remaining 39 children were scheduled for vaccination. Post-vaccination antibody titers confirmed that all children became seropositive for each disease. There was no complication in any patient.

CONCLUSION

Immunization against hepatitis B, hepatitis A, measles, mumps, rubella and varicella is insufficient in a considerable number of children with ITP, Hepatitis B Virus (HBV) and Hepatitis A Virus (HAV) immunization being the most frequently inadequate. After immunization, adequate seroconversion levels were achievable without complications.

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.

Vaccination in children with inherited bleeding disorders: Does the use of plasma an d factor affect the response to the vaccine: An institutional registry

INTRODUCTION

We aimed to evaluate the vaccine seroconversion of paediatric patients with factor deficiency and to complete the missing vaccines. We also emphasize the importance of variables such as recombinant factor and plasma intake frequency.

MATERIAL AND METHODS

This prospective observational study includes children between 2 and 17 age diagnosed with inhered factor deficiency. Seroconversion of hepatitis A, hepatitis B, varicella, measles, rubella and mumps vaccines were screened according to Ministry of Health Vaccination Schedule, it was completed if there were seronegative vaccines and the vaccine seroconversion was examined after vaccination approximately 1-6 months.

RESULTS

A total of 61 children were included in the study [mean age 11.2±5.1 years (2-18)], 49 (80.3%) were males. Factor VIII deficiency constituted 60.7%, factor XI 14.8%, factor VII 13.1 %, factor IX 9.8%, factor X 1.6% of the cases. None of the children had clinically important injection site complications such as uncontrollable bleeding or gross hematoma and vaccination does not induce the development of inhibitor. Measles antibody positivity was significantly lower in those who received factor 3 or 4 days times a week compared to those who received it when necessary (p = .049).

DISCUSSION AND CONCLUSION

This is the first study evaluating the vaccine conversion patients with inherited factor deficiency receiving plasma and plasma derived factor concentrates. It should be considered that children with haemophilia and their families may have vaccination hesitancy; therefore, follow-up of these patients should include a specified vaccination program to ensure adequate immunization of these patients.

A previously treated severe haemophilia A patient developed high-titre inhibitor after vaccinations

The factor VIII (FVIII)-neutralizing antibody (inhibitor) seen in 25%–30% of patients with severe haemophilia A (SHA). Vaccination is a non-genetic risk factor of inhibitor development as ‘danger signal’ which may provide a pro-inflammatory microenvironment to increase FVIII immunogenicity. We reported a previously treated SHA patient postponed the first vaccination to 15-month age received diphtheria-pertussis-tetanus intramuscularly. At 18-month age, the patient received Hepatitis A intramuscularly and Varicella Zoster Virus subcutaneously with 2 weeks interval and FVIII infusion was given <24 h prior for each. Successive bleedings occurred 1 week later with inefficacy of FVIII replacement. High-titre inhibitor was tested at 117 exposure days. This case suggested that continuous vaccinations in close proximity to FVIII could induce inhibitor. The relationship between vaccination and FVIII immunogenicity still needs to be revealed by further study.

Consensus Recommendations for Intramuscular COVID-19 Vaccination in Patients with Hemophilia

BACKGROUND

 Currently available coronavirus disease 2019 (COVID-19) vaccines are approved for intramuscular injection and efficacy may not be ensured when given subcutaneously. For years, subcutaneous vaccination was recommended in patients with hemophilia to avoid intramuscular bleeds. Therefore, recommendations for the application of COVID-19 vaccines are needed.

METHODS

 The Delphi methodology was used to develop consensus recommendations. An initial list of recommendations was prepared by a steering committee and evaluated by 39 hemophilia experts. Consensus was defined as ≥75% agreement and strong consensus as ≥95% agreement, and agreement as a score ≥7 on a scale of 1 to 9. After four rounds, a final list of statements was compiled.

RECOMMENDATIONS

 Consensus was achieved that COVID-19 vaccines licensed only for intramuscular injection should be administered intramuscularly in hemophilia patients. Prophylactic factor replacement, given on the day of vaccination with a maximum interval between prophylaxis and vaccination of 24 hours (factor VIII and conventional factor IX concentrates) or 48 hours (half-life extended factor IX), should be provided in patients with moderate or severe hemophilia. Strong consensus was achieved that patients with mild hemophilia and residual factor activity greater than 10% with mild bleeding phenotype or patients on emicizumab usually do not need factor replacement before vaccination. Swelling, erythema, and hyperthermia after vaccination are not always signs of bleeding but should prompt consultation of a hemophilia care center. In case of injection-site hematoma, patients should receive replacement therapy until symptoms disappear.

CONCLUSIONS

 Consensus was achieved on recommendations for intramuscular COVID-19 vaccination after replacement therapy for hemophilia patients depending on disease severity.