Economic evaluations of Haemophilus influenzae type b (Hib) vaccine: a systematic review

Hib Vaccines: Their Impact on Haemophilus influenzae Type b Disease

Haemophilus influenzae serotype b (Hib) is an important cause of serious, invasive infections, particularly in young children. Since 1985, a series of vaccines composed of the type b capsular polysaccharide polyribosylribitol phosphate (PRP), followed by PRP conjugated to various proteins, have been licensed for use in the United States and worldwide. The conjugated vaccines offer increased immunogenicity and prolonged durability of immune protection compared to the plain PRP vaccine and increasingly are combined with other childhood vaccines for decreased cost and increased ease of vaccination. Hib vaccines have a very favorable safety profile, have been found to be either cost-saving or cost-effective by many public health agencies, and, in most countries, are initiated during early infancy as part of routine childhood immunization programs. As a result of widespread use of the vaccines, the incidence of Hib infections, and their associated morbidity and mortality, has fallen dramatically across the globe. Yet, many children remain unimmunized or underimmunized against Hib, particularly in limited-resource countries. Future efforts to further reduce the disease burden of Hib infections remain a high priority.

Canadian Association of Gastroenterology Clinical Practice Guideline for Immunizations in Patients With Inflammatory Bowel Disease (IBD)-Part 2: Inactivated Vaccines

BACKGROUND AND AIMS

The effectiveness and safety of vaccinations can be altered by immunosuppressive therapies, and perhaps by inflammatory bowel disease (IBD) itself. These recommendations developed by the Canadian Association of Gastroenterology and endorsed by the American Gastroenterological Association, aim to provide guidance on immunizations in adult and pediatric patients with IBD. This publication focused on inactivated vaccines.

METHODS

Systematic reviews evaluating the efficacy, effectiveness, and safety of vaccines in patients with IBD, other immune-mediated inflammatory diseases, and the general population were performed. Critical outcomes included mortality, vaccine-preventable diseases, and serious adverse events. Immunogenicity was considered a surrogate outcome for vaccine efficacy. Certainty of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. Key questions were developed through an iterative online platform, and voted on by a multidisciplinary group. Recommendations were formulated using the Evidence-to-Decision framework. Strong recommendation means that most patients should receive the recommended course of action, whereas a conditional recommendation means that different choices will be appropriate for different patients.

RESULTS

Consensus was reached on 15 of 20 questions. Recommendations address the following vaccines: Haemophilus influenzae type b, recombinant zoster, hepatitis B, influenza, pneumococcus, meningococcus, tetanus-diphtheria-pertussis, and human papillomavirus. Most of the recommendations for patients with IBD are congruent with the current Centers for Disease Control and Prevention and Canada's National Advisory Committee on Immunization recommendations for the general population, with the following exceptions. In patients with IBD, the panel suggested Haemophilus influenzae type b vaccine for patients older than 5 years of age, recombinant zoster vaccine for adults younger than 50 year of age, and hepatitis B vaccine for adults without a risk factor. Consensus was not reached, and recommendations were not made for 5 statements, due largely to lack of evidence, including double-dose hepatitis B vaccine, timing of influenza immunization in patients on biologics, pneumococcal and meningococcal vaccines in adult patients without risk factors, and human papillomavirus vaccine in patients aged 27-45 years.

CONCLUSIONS

Patients with IBD may be at increased risk of some vaccine-preventable diseases. Therefore, maintaining appropriate vaccination status in these patients is critical to optimize patient outcomes. In general, IBD is not a contraindication to the use of inactivated vaccines, but immunosuppressive therapy may reduce vaccine responses.

Antimicrobial immunotherapeutics: past, present and future

In this age of antimicrobial resistance (AMR) there is an urgent need for novel antimicrobials. One area of recent interest is in developing antimicrobial effector molecules, and even cell-based therapies, based on those of the immune system. In this review, some of the more interesting approaches will be discussed, including immune checkpoint inhibitors, Interferons (IFNs), Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF), Chimeric Antigen Receptor (CAR) T cells, Antibodies, Vaccines and the potential role of trained immunity in protection from and/or treatment of infection.

Etiology, Treatment, and Outcome of Children Aged 3 to 36 Months With Fever Without a Source at a Community Hospital in Southern Thailand

Background: Fever without a source (FWS) in young children can result from occult bacteremia, urinary tract infection (UTI), meningitis, or certain viral infections. In rural areas of Thailand, where bacterial cultures are not available in some community hospitals, the appropriate examination and management of FWS remain controversial. Methods: We retrospectively searched electronic medical records for medical diagnoses associated with FWS and evaluated the characteristics and clinical courses of children aged 3 to 36 months with FWS who were admitted to a community hospital in southern Thailand between January 2015 and December 2016. Results: Sixty-seven children aged 3 to 36 months with an initial diagnosis of FWS were enrolled. The median age was 11 months (interquartile range [IQR] 8-21 months). Complete blood counts, blood cultures, urine analysis results and urinary cultures were obtained from 67 (100.0%), 31 (46.3%), 47 (70.1%), and 7 (10.5%) patients, respectively. The most common empirical antibiotic administered to these patients was ceftriaxone (71.6%); however, 4 patients recovered without antibiotic administration. The median duration of intravenous antibiotic administration was 4 days (IQR 2-4 days). Intravenous antibiotics were replaced by oral antibiotics in 38 patients (62.3%). The median time to fever subsidence was 30 hours (IQR 12-60 hours). Regarding final diagnoses, 5 patients (7.5%) were diagnosed with culture-confirmed UTI, and 2 (3.0%) had bacteremia (due to contamination). The majority of the children (60, 89.6%) retained the diagnosis of FWS. Presentation at the hospital was significantly earlier in children with culture-confirmed UTI (median 1 day) than in those with culture-negative FWS (median 3 days) (P = .019). Discussion: We evaluated the characteristics and clinical courses of young children with FWS presenting at a community hospital and the treatment approaches utilized by physicians. Although all patients had good prognoses during the study period, we identified several areas for improvement in conducting proper examinations (especially assessments for UTI in children presenting within the first day of fever onset).

Accelerating Typhoid Conjugate Vaccine Introduction: What Can Be Learned From Prior New Vaccine Introduction Initiatives?

The health consequences of typhoid, including increasing prevalence of drug-resistant strains, can stress healthcare systems. While vaccination is one of the most successful and cost-effective health interventions, vaccine introduction can take years and require considerable effort. The Typhoid Vaccine Acceleration Consortium (TyVAC) employs an integrated, proactive approach to accelerate the introduction of a new typhoid conjugate vaccine to reduce the burden of typhoid in countries eligible for support from Gavi, the Vaccine Alliance. TyVAC and its partners are executing a plan, informed by prior successful vaccine introductions, and tailored to the nuances of typhoid disease and the typhoid conjugate vaccine. The iterative process detailed herein summarizes the strategy and experience gained from the first 2 years of the project.