Hib Vaccine Research Articles

Determination of Anti-Hib Type B Antibodies Level and Vaccination Coverage in Children Aged 6-7 Months, 18 Months After the Introduction of the Hib Vaccine in the District of Bamako-Mali

Determination of Anti-Hib Type B Antibodies Level and Vaccination Coverage in Children Aged 6-7 Months, 18 Months After the Introduction of the Hib Vaccine in the District of Bamako-Mali

Use of Haemophilus influenzae Type b-Containing Vaccines Among American Indian and Alaska Native Infants: Updated Recommendations of the Advisory Committee on Immunization Practices - United States, 2024.

Invasive Haemophilus influenzae type b (Hib) disease is a serious bacterial infection that disproportionally affects American Indian and Alaska Native (AI/AN) populations. Hib vaccination with a monovalent Hib conjugate vaccine consisting of Hib capsular polysaccharide (polyribosylribitol phosphate [PRP]) conjugated to outer membrane protein complex of Neisseria meningitidis serogroup B, PRP-OMP (PedvaxHIB, Merck and Co., Inc.) has historically been preferred for AI/AN infants, who are at increased risk for invasive Hib disease, because it provides substantial protection after the first dose. On June 26, 2024, CDC's Advisory Committee on Immunization Practices (ACIP) recommended that a hexavalent, combined diphtheria and tetanus toxoids and acellular pertussis (DTaP), inactivated poliovirus (IPV), Hib conjugate, and hepatitis B (HepB) vaccine, DTaP-IPV-Hib-HepB (Vaxelis, MSP Vaccine Company) should be included with monovalent PRP-OMP in the preferential recommendation for AI/AN infants because of the PRP-OMP Hib component. A primary Hib vaccination series consisting of either 1) monovalent PRP-OMP (2-dose series at ages 2 and 4 months) or 2) DTaP-IPV-Hib-HepB (3-dose series at ages 2, 4, and 6 months) is preferred for AI/AN infants. DTaP-IPV-Hib-HepB is only indicated for use in infants at ages 2, 4, and 6 months and should not be used for the booster doses of Hib, DTaP, or IPV vaccines. For the booster dose of Hib vaccine, no vaccine formulation is preferred for AI/AN children; any Hib vaccine (except DTaP-IPV-Hib-HepB) should be used. This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of Hib-containing vaccines among AI/AN infants and children.

Post-Marketing Surveillance of Adverse Events Following Immunization with Haemophilus Influenzae Type b Conjugate Vaccine - China, 2010-2021.

The Haemophilus influenzae type b (Hib) conjugate vaccine is widely administered in China. We extracted data on Hib vaccine doses administered and adverse events following immunization (AEFI) reported between 2010 and 2021 from the Chinese National Immunization Information System (CNIIS). A descriptive analysis was conducted to examine the characteristics and incidence rates of AEFI with the Hib vaccine. In China, between 2010 and 2021, a total of 52,910 AEFIs with the Hib vaccine were reported, resulting in an overall AEFI reporting rate of 38.10 per 100,000 doses. Common (typically minor) and rare (potentially serious) vaccine reactions occurred at rates of 34.71 and 2.78 per 100,000 doses, respectively. Among the common vaccine reactions, the incidences of fever (axillary temperature ≥38.6 ℃), injection site redness and swelling (>2.5 cm in diameter), and injection site induration (>2.5 cm in diameter) were 11.93, 9.69, and 3.38 per 100,000 doses, respectively. Rare vaccine reactions included anaphylactic rash, angioedema, and febrile convulsion with reported incidences of 2.42, 0.10, and 0.05 per 100,000 doses, respectively. The incidence of serious rare vaccine reactions was 0.16 per 100,000 doses. The reported incidence of AEFI with the Hib vaccine was low, with the occurrence of serious rare adverse reactions also being markedly low throughout the period 2010-2021 in China.

Efficacy and Prolonged Safety of Haemophilus influenzae Type b Conjugate Vaccines.

The purpose of this study was to find data proving the influence of the Haemophilus influenzae type b (Hib) conjugate vaccination on the frequency of invasive Hib illness. A systematic literature search was conducted on the PubMed database to identify peerreviewed publications pertaining to the epidemiology of Haemophilus influenzae meningitis, both before and after the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines. The search query employed a combination of relevant keywords, including "invasive," "Haemophilus," "influenzae," "meningitis," and specific serotype b (Hib). Additionally, terms related to epidemiology, burden, risk factors, impact, Hib vaccine, Hib conjugate vaccine, combination vaccine, vaccine production, efficacy, immunisation coverage, surveillance, review, clinical aspects, outcomes, and various age groups (adults and children) were incorporated. The search encompassed articles published till now. Subsequently, relevant research papers concerning Haemophilus influenzae meningitis were subjected to a comprehensive review and analysis. The Hib conjugate vaccination has shown to be extremely effective when administered to the entire population. However, changes to the immunisation protocol appear to be required in order to effectively manage invasive Hib illness.

Adverse events following immunization of co- and separate administration of DTaP-IPV/Hib vaccines: A real-world comparative study

ABSTRACT To fully understand the safety of DTaP-IPV/Hib vaccination, we evaluated the differences between DTaP-IPV/Hib co-administration and separate administration of the DTaP, IPV and Hib vaccines (DTaP+IPV+Hib) based on adverse events following immunization (AEFI). All AEFI reported in Hebei Province, China, between 2020 and 2022 were included in this study. The risk difference (RD%), relative risk (RR), and Chi-square value were used to compare the differences in reported rates of AEFI between the DTaP-IPV/Hib and DTaP+IPV+Hib groups. From 2020 to 2022, 130 AEFI cases were reported in Hebei Province after DTaP-IPV/Hib vaccination, corresponding to an AEFI reported rate of 66.9/million doses, which was significantly lower than that for DTaP+IPV+Hib (9836 AEFI with a reported rate of 637.8/million doses). The overall reported rate of non-severe AEFI for DTaP+IPV+Hib vaccines was 9.5 times that of DTaP-IPV/Hib vaccination [95% confidence interval (CI): 8.0, 11.3]. Meanwhile, the reported rate of AEFI among infants aged 0–1 y was 9.8 times higher for DTaP+IPV+Hib than for DTaP-IPV/Hib (95% CI: 8.2, 11.7). DTaP+IPV+Hib vaccination also resulted in higher risks of high fever, localized redness and swelling, localized induration, and allergic rash compared with DTaP-IPV/Hib vaccination. The risk of AEFI, which were mostly mild reaction, was higher after vaccination with DTaP+IPV+Hib than after DTaP-IPV/Hib vaccination.

Epidemiological and bacterial profile ofchildhood meningitis in Tunisia.

The worldwide burden of disease of bacterial meningitis remains high, despite the decreasing incidence following introduction of routine vaccination campaigns.The aim of our study was to evaluate the epidemiological and bacteriological profile of paediatric bacterial meningitis (BM) in Tunisian children, during the period 2003-2019, following the implementation of Haemophilus influenzae type b (Hib) vaccine (April 2011) and before 10-valent pneumoccocal conjugate vaccine (PCV10) introduction to the childhood immunization program.All bacteriologically confirmed cases of BM admitted to children's hospital of Tunis were recorded (January 2003 to April 2019). Serogroups of Neisseria meningitidis (Nm) and serotypes of Streptococcus pneumoniae (Sp) and H. influenzae (Hi) and antibiotic resistance were determined using conventional and molecular methods.Among 388 cases, the most frequent species were Sp (51.3%), followed by Nm (27.5%) and Hi(16.8%). We observed a significant decrease in Hi BM rate during the conjugated Hib vaccine use period (P < 0.0001). The main pneumococcal serotypes were 14, 19F, 6B, 23F and 19A and the serotype coverage of PCV10, PCV13, PCV15 and PCV20 was 71.3 and 78.8%, 79.4 and 81.9% respectively. Themost frequent Nm serogroup was B (83.1%). Most Hi strains were of serotype b (86.9%). High levels of resistance were found: Sp and Nm to penicillin (respectively 60.1 and 80%) and Hi to ampicillin (42.6%). All meningococcal and Hi isolates were susceptible to third-generation cephalosporins and 7.2% of pneumococcal strains had decreased susceptibility to these antibiotics.The Hib conjugate vaccine decreased the rate of BM. Sp dominated the aetiology of BM in children in Tunisia. Conjugate vaccines introducing decreases not only BM cases but also antimicrobial resistance.

Septic Arthritis of the Hip Joint Secondary to Haemophilus Influenza in Immunized Teenager: A Case Report

Septic arthritis is an infection to one joint or more that mainly happens after a hematogenous spread of an infection causing inflammation to the joint. Large joints such as hip and knee are more commonly affected, however, septic arthritis can happen in any other joints such as shoulders and ankles. Staphylococcus aureus is the most frequently isolated pathogen in this condition; however, other bacteria, viruses, fungi, and mycobacterium can also cause septic arthritis. Haemophilus influenzae type b (Hib) is the most common subtype of Haemophilus influenza and is primarily affecting children and those with compromised immune systems. Haemophilus influenza usually causes lower respiratory tract infections, including pneumonia. In addition, they can induce numerous other severe infections, such as bacteremia, empyema, meningitis, cellulitis, and septic arthritis. The Hib conjugate vaccine has significantly reduced the incidence of Hib infections and is effective in protecting against capsular polysaccharide type b. the CDC recommends administering a conjugate Hib vaccine series beginning at age 2 months, or 6 weeks followed by boosters at age of12 to 15 months. In this article, we are reporting a unique case of hip septic joint in a fully vaccinated teenager, and it is the first case reported in the literature to our knowledge.

Trends in serotype distribution and antimicrobial susceptibility pattern of invasive Haemophilus influenzae isolates from Brazil, 2009-2021.

Invasive Haemophilus influenzae (Hi) disease poses a significant global health challenge. With the relaxation of COVID-19 pandemic measures and declining H. influenzae serotype b (Hib) vaccination coverage, there is concern about a potential increase in Hi cases worldwide. This study analyzed 1437 invasive Hi isolates in Brazil over 13years, determining capsular serotypes, antimicrobial susceptibility, and genetic relatedness through multilocus sequence typing. The primary source of isolation for these invasive H. influenzae isolates was blood (54.4%), followed by cerebrospinal fluid (37.1%) and lung specimens (8.5%), respectively. Consequently, bacteremia (47%) was the most common clinical presentation, followed by meningitis (39.6%) and pneumonia (13.4%). Non-encapsulated Hi (NTHi) predominated among the isolates (51.4%), along with serotype a (22%) and serotype b (21.5%) among the encapsulated isolates. The majority of the encapsulated isolates were isolated from children under 14years of age (76.7%), while NTHi isolates were identified in patients older than 15years, particularly those ≥ 60years old (40%). Ampicillin resistance was observed in 17.1% of cases, displaying β-lactamase production as the principal resistance mechanism. MLST revealed a diverse NTHi population, whereas the encapsulated isolates presented a clonal structure. This study describes the prevalence of NTHi isolates circulating in Brazil after two decades of the Hib vaccine immunization program. Continuous universal surveillance is crucial for implementing prompt public health measures to prevent and control invasive Hi disease and monitor changes in antibiotic resistance profiles.

Awareness About Child Immunization among Women in Rural Area of District Jalaun

Introduction; Universal Immunization Programme (UIP) is one of the largest public health programmes targeting close of 2.67 crore newborns and 2.9 crore pregnant women annually. It is one of the most cost-effective public health interventions and largely responsible for reduction of vaccine preventable under-5 mortality rate. Under UIP, immunization is providing free of cost against 12 vaccine preventable diseases. Mission Indra dhanush (MI) was launched in December 2014 and aims at increasing the full immunization coverage to children to 90 % (1). Mother play a very important role in child immunization, so awareness and correct knowledge about immunization is very essential in women, keeping this thing in mind, the present study was undertaken. Aims and objectives;1. To assess the awareness about child immunization among women in rural area.2. To know the correct knowledge of vaccine given in children among women .Material and methods;A cross sectional study was carried out in a rural area of district Jalaun. Aata block was selected randomly for study area. RHTC Aata was selected and women attending the OPD during month of August to October were included in study. Sample size were calculated and 140 mothers were interviewed by using predesigned and pretested questionnaire after taking verbal consent and data was collected and analyzed using appropriate statistical tool. Results; mostly women had heard about immunization in children (82.1%) and most of the women got information from health workers like ASHA/ANM followed by family and friends. vaccine given to child that shows knowledge about BCG/POLIO/MMR was found good but average about DPT and HEPATITIS. Very few women had knowledge about HIB, JE and ROTA vaccine. Conclusion; need to focus on education and awareness programme on women regarding child immunization in rural areas.

Abstract 6637: The Haemophilus influenzae vaccine mitigates pancreatic tumor progression and lowers immunoregulatory cell levels in the tumor microenvironment

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease projected to become the second leading cause of cancer deaths by 2030. First-line chemotherapies gemcitabine and FOLFIRINOX provide little therapeutic benefit and are accompanied by severe adverse toxicities, precluding long-term treatment. In addition, PDAC is notoriously refractory to checkpoint inhibitor immunotherapies, due to poor immunogenicity and a tumor microenvironment dominated by suppressive cell types. Thus, there is an unmet need for innovative, immune-based strategies to combat PDAC. A previous study utilized engineered bacteria to effectively kill PDAC tumor cells by directly delivering immunogenic tetanus toxoid to the tumor. Given the potential toxicity in using live bacteria, our group utilized a less toxic alternative, an FDA-approved Haemophilus influenzae type b vaccine (HibVx) also containing a tetanus toxoid component. To determine the antitumor potential of HibVx, our group used a physiologically relevant murine model, low T cell clone murine PDAC tumor model 641c95 and clinically relevant KPC mice model for PDAC. After tumors were established, animals received three consecutive daily treatments of HibVx via intraperitoneal injection. HibVx-treated animals experienced a dramatic reduction in tumor growth compared to PBS-treated controls (p&amp;lt;0.001). Given that tetanus toxoid is highly immunogenic in nature, changes in intratumoral immune cell populations following HibVx treatments were of great interest. Using flow cytometry analysis, HibVx-treated tumors had a significant increase in natural killer cells compared to control tumors (p&amp;lt;0.05). In addition, HibVx affected myeloid-derived suppressor cell populations (MDSCs), which are heavily implicated in the suppressive nature of PDAC tumors. HibVx also significantly decreased MDSCs within the tumor (p&amp;lt;0.05). In all, these findings position HibVx as an effective immunostimulatory agent that can be used as an alternative to live bacteria-based therapy for the treatment of PDAC. Citation Format: Eileena F. Giurini, Sam G. Pappas, Kajal H. Gupta. The Haemophilus influenzae vaccine mitigates pancreatic tumor progression and lowers immunoregulatory cell levels in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6637.

An Investigation of Pediatric Case-patients With Invasive Haemophilus influenzae in Alaska, 2005-2011.

Haemophilus influenzae (Hi) can cause severe disease in children. This study aimed to identify risk factors related to invasive Hi disease in Alaska children and evaluate carriage in people around them. From 2005 to 2011, we investigated episodes of invasive, typeable Hi disease in Alaska children <10 years old. Three age-matched control children were enrolled for each case-patient. We evaluated oropharyngeal Hi carriage in people in close contact with Hi case-patients (contacts) as well as control children and their household members. Individual and household risk factors for illness and carriage were evaluated using questionnaires and chart reviews. Thirty-eight of 44 (86%) children with invasive, typeable Hi disease were recruited: 20 Hi serotype a (53%), 13 serotype b (Hib) (34%) and 5 serotype f (13%). Children with the invasive Hi disease were more likely than controls to have underlying health problems (67% vs. 24%, P = 0.001), other carriers of any Hi in their household (61% vs. 15%, P < 0.001), and inadequate Hib vaccination (26% vs. 9%, P = 0.005). People who carried Hi were younger than noncarriers (mean 12.7 vs. 18.0 years, P = 0.008). The carriage was clustered within case-patient households, with carriage in 19% of household contacts, while only 6.3% of nonhousehold contacts and 5.5% of noncontacts carried the Hi serotype of interest ( P < 0.001). Factors associated with invasive Hi disease in children included underlying health problems, household carriage and inadequate Hib vaccination. The high level of carriage in case-patient households is important to consider when evaluating treatment and prophylaxis strategies.

Predicting the potential impact of scaling up four pneumonia interventions on under-five pneumonia mortality: A prospective Lives Saved Tool (LiST) analysis for Bangladesh, Chad, and Ethiopia.

Pneumonia remains the leading cause of mortality in under-five children outside the neonatal period. Progress has slowed down in the last decade, necessitating increased efforts to scale up effective pneumonia interventions. We used the Lives Saved Tool (LiST), a modelling software for child mortality in low- and middle-income settings, to prospectively analyse the potential impact of upscaling pneumonia interventions in Bangladesh, Chad, and Ethiopia from 2023 to 2030. We included Haemophilus influenzae type B (Hib) vaccination, pneumococcal conjugate vaccine (PCV), oral antibiotics, pulse oximetry, and oxygen as pneumonia interventions in our analysis. Outcomes of interest were the number of pneumonia deaths averted, the proportion of deaths averted by intervention, and changes in the under-five mortality rate. We found that 19 775 lives of children under-five could be saved in Bangladesh, 76 470 in Chad, and 97 343 in Ethiopia by scaling intervention coverages to ≥90% by 2030. Our estimated reductions in pneumonia deaths among children under five range from 44.61% to 57.91% in the respective countries. Increased coverage of oral antibiotics, pulse oximetry, and oxygen show similar effects in all three countries, averting between 18.80% and 23.65% of expected pneumonia deaths. Scaling-up PCV has a prominent effect, especially in Chad, where it could avert 14.04% of expected pneumonia deaths. Under-five mortality could be reduced by 1.42 per 1000 live births in Bangladesh, 22.52 per 1000 live births in Chad, and 5.48 per 1000 live births in Ethiopia. This analysis shows the high impact of upscaling pneumonia interventions. The lack of data regarding coverage indicators is a barrier for further research, policy, and implementation, all requiring increased attention.

PREVALENCE AND RISK FACTORS OF HEMOPHILUS INFLUENZA TYPE B MENINGITIS: ROLE OF VACCINATION AND SOCIAL DEMOGRAPHY IN THE PATHOGENESIS

Bacterial meningitis is a condition caused by a bacterial infection in the meninges that results in inflammation. The causative agent varies according to age and other related factors. Hemophilus Influenza type B (Hib) is the most common cause of meningitis in children. This study aimed to determine the prevalence of H. influenza meningitis, the role of vaccination, and demographic factors in the etiology of Hib meningitis. Using a cross-sectional design, the study was conducted at the Pediatrics department of Ayub Teaching Hospital, Abbottabad, for six months, from 19-9-2023 to 19-3-2024. After obtaining ethical approval from the IRB of Ayub Teaching Hospital Abbottabad, a cross-sectional study was conducted, and 143 patients who met the inclusion criteria were included in the study. Hib vaccination status was confirmed by history and the presence of a vaccination card. Cerebrospinal fluid (CSF) was collected and sent for analysis, including microscopy and culture. The mean age of the patients was 44.92±51.48 months, with a male-to-female ratio of 1.38:1. Seventy (49.65%) patients were fully vaccinated against the Hib virus. The study results showed that H. influenza growth on CSF culture was noted in 14 (9.79%) patients. The Hib positive status of these cases was significantly associated with gender, residential area, and socioeconomic class of the patient at p values of 0.005, 0.047, and 0.041. In conclusion, despite the use of conjugate vaccine, Hib remains a cause of meningitis, and the pathogenesis of Hib meningitis is associated with gender, residential category, and socioeconomic class of the patient.

Non-specific effects of Pneumococcal and Haemophilus vaccines in children aged 5 years and under: a systematic review

ObjectiveTo determine the evidence for non-specific effects of the Pneumococcal and Haemophilus influenza vaccine in children aged 5 years and under.Data sourcesA key word literature search of MEDLINE, EMBASE, The...

Evolution of Haemophilus influenzae infection during the vaccination period: literature review

Mass immunization with H. influenzae type b (Hib) vaccines has led to a sharp decrease in the incidence of invasive and non-invasive forms of Haemophilus influenza infection. H. influenzae causes a diverse spectrum of diseases from usually asymptomatic carriage to otitis, sinusitis, epiglottitis, pneumonia, endopericarditis, inflammation of the subcutaneous tissue, arthritis, and is one of the four main causative agents of bacterial meningitis. Materials and methods. In order to identify the significance of Hemophilus influenzae infection during the vaccination period, an analysis was carried out on the spread of Hemophilus influenzae infection, its clinical forms, as well as the antibiotic resistance of the pathogen. A review of domestic and foreign publications over the past 20 years was conducted in the search engines PubMed, Google Scholar, Cochrane Library and Elibrary. Results. Studies conducted in various countries show that after the start of mass immunization, H. influenzae type b is no longer the dominant serotype of the pathogen causing invasive infections in most countries. Everywhere in the world, the leading positions are occupied by cases of infection caused by non-typable serotypes of H. influenzae type a, f, b (Hia, Hif, Hib) predominate among the capsular forms. Unprotected aminopenicillins, second-generation cephalosporins, and sulfonamides are the leading classes of antibacterial drugs to which H. influenzae strains have developed resistance. A variety of clinical forms is still relevant for hemophilic infection. Bacteremia, meningitis, and pneumonia are the main clinical manifestations of invasive Haemophilus influenzae infection caused by typed and non-typed serotypes of the pathogen.

A Hib vaccine battle with Haemophilus influenzae

With nearly 386,000 deaths caused by Haemophilus influenzae reported by WHO, Haemophilus influenzae is one of the worst killers of children under the age of five. Nowadays, there are places still prone to invasive Hib infections, and numerous areas are still susceptible to Hib-related illnesses. Haemophilus influenza is a bacterium plaguing many families, particularly those with young children. However, antibiotic resistance is increasing. The Hib vaccine may be another solution. The prevalence of Hib infection has dropped significantly after the launch of Hib immunization. The Hib combination vaccination, however, does not protect against all bacterial types. Consequently, certain people may benefit from receiving medical therapy. However, at present, peoples understanding of Hib vaccine in many areas is still limited. This study present a thorough and critical evaluation of the most recent understanding of H.influenzae and the medication: Hib vaccine. The focus of this review is to provide an overview of current research on Haemophilus influenzae and also covers how the vaccine works and its advantages and disadvantages.

In Vivo Validation of Novel Synthetic tbp1 Peptide-Based Vaccine Candidates against Haemophilus influenzae Strains in BALB/c Mice.

Haemophilus influenzae is a Gram-negative bacterium characterized as a small, nonmotile, facultative anaerobic coccobacillus. It is a common cause of a variety of invasive and non-invasive infections. Among six serotypes (a-f), H. influenzae type b (Hib) is the most familiar and predominant mostly in children and immunocompromised individuals. Following Hib vaccination, infections due to other serotypes have increased in number, and currently, there is no suitable effective vaccine to induce cross-strain protective antibody responses. The current study was aimed to validate the capability of two 20-mer highly conserved synthetic tbp1 (transferrin-binding protein 1) peptide-based vaccine candidates (tbp1-E1 and tbp1-E2) predicted using in silico approaches to induce immune responses against H. influenzae strains. Cytokine induction ability, immune simulations, and molecular dynamics (MD) simulations were performed to confirm the candidacy of epitopic docked complexes. Synthetic peptide vaccine formulations in combination with two different adjuvants, BGs (Bacterial Ghosts) and CFA/IFA (complete/incomplete Freund's adjuvant), were used in BALB/c mouse groups in three booster shots at two-week intervals. An indirect ELISA was performed to determine endpoint antibody titers using the Student's t-distribution method. The results revealed that the synergistic use of both peptides in combination with BG adjuvants produced better results. Significant differences in absorbance values were observed in comparison to the rest of the peptide-adjuvant combinations. The findings of this study indicate that these tbp1 peptide-based vaccine candidates may present a preliminary set of peptides for the development of an effective cross-strain vaccine against H. influenzae in the future due to their highly conserved nature.

Systematic Evaluation of the Distribution of Immune Cells following Subcutaneous Administration of Haemophilus Influenzae Type B Vaccine to Mice.

The Haemophilus influenzae type B (Hib) conjugate vaccine is the most effective way to prevent Hib infection in infants and young children, and it is designed to induce the production of antibodies against polyribosylribitol phosphate (PRP) to protect babies from infection. However, the mechanism of immunity induced by the Hib vaccine is not fully understood. Recently, with the development of the combination diphtheria and tetanus toxoids and acellular pertussis vaccines (DTaP), increasing numbers of manufacturers have begun to develop DTaP-based combination vaccines, like the combination vaccine diphtheria and tetanus toxoids and acellular pertussis and Hib conjugate vaccine (DTaP-Hib), which contains adjuvants. However, the Hib vaccine does not contain adjuvants. It was theorized that the Hib antigen has poor compatibility with aluminum adjuvants for unclear reasons. Therefore, understanding the mechanism of the Hib-vaccine-induced immune response and the influence of adjuvants on the Hib vaccine is of great significance. In this paper, we immunized BalBc mice with either the Hib vaccine or the Hib vaccine that adsorbs aluminum adjuvants (Hib-Al). Here, we analyzed the anti-PRP antibody level and immune response of different cells using cell and cytokine levels. We found that the Hib vaccine could induce a humoral and cellular immune response, and the Hib-Al vaccine could induce greater quantities of IFN-γ, IL-4, and IL-6 and more antigen-specific antibodies through B cells, Th1, Th2, and ILC3s in the spleen. Together, our findings demonstrate the serologic responses and immune response in terms of cell and cytokine levels induced by the Hib vaccine, and they also imply that the addition of aluminum hydroxide adjuvant could enhance the function of the Hib vaccine, which preliminarily reveals the mechanism of immune response induced by the Hib-related vaccine.

Immunization coverage, knowledge, satisfaction, and associated factors of non-National Immunization Program vaccines among migrant and left-behind families in China: evidence from Zhejiang and Henan provinces

BackgroundMigrant and left-behind families are vulnerable in health services utilization, but little is known about their disparities in immunization of non-National Immunization Program (NIP) vaccines. This study aims to evaluate the immunization coverage, knowledge, satisfaction, and associated factors of non-NIP vaccines among local and migrant families in the urban areas and non-left-behind and left-behind families in the rural areas of China.MethodsA cross-sectional survey was conducted in urban areas of Zhejiang and rural areas of Henan in China. A total of 1648 caregivers of children aged 1–6 years were interviewed face-to-face by a pre-designed online questionnaire, and their families were grouped into four types: local urban, migrant, non-left-behind, and left-behind. Non-NIP vaccines included Hemophilus influenza b (Hib) vaccine, varicella vaccine, rotavirus vaccine, enterovirus 71 vaccine (EV71) and 13-valent pneumonia vaccine (PCV13). Log-binomial regression models were used to calculate prevalence ratios (PRs) and 95% confidence intervals (CIs) for the difference on immunization coverage of children, and knowledge and satisfaction of caregivers among families. The network models were conducted to explore the interplay of immunization coverage, knowledge, and satisfaction. Logistic regression models with odds ratios (ORs) and 95% CIs were used to estimate the associated factors of non-NIP vaccination.ResultsThe immunization coverage of all non-NIP vaccines and knowledge of all items of local urban families was the highest, followed by migrant, non-left-behind and left-behind families. Compared with local urban children, the PRs (95% CIs) for getting all vaccinated were 0.65 (0.52–0.81), 0.29 (0.22–0.37) and 0.14 (0.09–0.21) among migrant children, non-left-behind children and left-behind children, respectively. The coverage-knowledge-satisfaction network model showed the core node was the satisfaction of vaccination schedule. Non-NIP vaccination was associated with characteristics of both children and caregivers, including age of children (> 2 years-OR: 1.69, 95% CI: 1.07–2.68 for local urban children; 2.67, 1.39–5.13 for migrant children; 3.09, 1.23–7.76 for non-left-behind children); and below caregivers’ characteristics: family role (parents: 0.37, 0.14–0.99 for non-left-behind children), age (≤ 35 years: 7.27, 1.39–37.94 for non-left-behind children), sex (female: 0.49, 0.30–0.81 for local urban children; 0.31, 0.15–0.62 for non-left-behind children), physical health (more than average: 1.58, 1.07–2.35 for local urban children) and non-NIP vaccines knowledge (good: 0.45, 0.30–0.68 for local urban children; 7.54, 2.64–21.50 for left-behind children).ConclusionsThere were immunization disparities in non-NIP vaccines among migrant and left-behind families compared with their local counterparts. Non-NIP vaccination promotion strategies, including education on caregivers, and optimization of the immunization information system, should be delivered particularly among left-behind and migrant families.Graphical

Factors associated with recommendation behaviors of four non-National Immunization Program vaccines: a cross-sectional survey among public health workers in China

BackgroundImmunization is a crucial preventive measure to safeguard children under five years old against a range of diseases. In China, the coverage rate of non-National Immunization Program (non-NIP) vaccines can be improved by leveraging the recommendation from public health workers. Hence, understanding the influencing factors of recommendation behaviors assume paramount importance. This study aims to investigate influencing factors of public health workers' recommendation behaviors towards non-NIP vaccines, with a particular emphasis on financial incentives.MethodsA cross-sectional survey was conducted using a multi-stage sampling method in 2019 from August to October. 627 public health workers were recruited from 148 community healthcare centers in ten provincial-level administrative divisions in China. An anonymous questionnaire was used to collect demographic information, attitudes towards vaccination, and recommendation behaviors towards non-NIP vaccines, including Haemophilus influenzae type b (Hib) vaccine, pneumococcal conjugate vaccine, varicella vaccine, and rotavirus vaccine. Descriptive analysis and multivariate logistic regression analysis were adopted in this study.ResultsOf the 610 public health workers with complete survey data, 53.8%, 57.4%, 84.1%, and 54.1% often recommended Hib vaccine, pneumococcal pneumonia vaccine (PCV), varicella vaccine, and rotavirus vaccine, respectively. Logistic regression revealed that gender (Hib vaccine: OR = 0.4, 95% CI: 0.2–0.8; PCV: OR = 0.4, 95% CI: 0.2–0.8; rotavirus vaccine: OR = 0.3, 95% CI: 0.2–0.6), financial incentives for non-NIP vaccination (Hib vaccine: OR = 1.9, 95% CI: 1.1–3.6; PCV: OR = 2.1, 95% CI: 1.1–3.9; rotavirus vaccine: OR = 2.0, 95% CI: 1.1–3.8) and perception of vaccine safety (Hib vaccine: OR = 2.7, 95% CI: 1.1–7.0; PCV: OR = 3.2, 95% CI: 1.2–8.0; rotavirus vaccine: OR = 3.0, 95% CI: 1.2–7.7) were associated with public health workers’ recommendation towards Hib vaccine, PCV and rotavirus vaccine.ConclusionsThe findings highlighted public health workers’ recommendation behaviors of non-NIP vaccines in China and revealed strong association between vaccine recommendation and financial incentives. This highlights the importance of financial incentives in public health workers’ recommendation toward non-NIP vaccines in China. Proper incentives are recommended for public health workers to encourage effective health promotion in immunization practices.Graphical