Facilitating the WHO expanded program of immunization: the clinical profile of a combined diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b vaccine

A phase III randomized-controlled study of safety and immunogenicity of DTwP-HepB-IPV-Hib vaccine (HEXASIIL®) in infants

A fully liquid hexavalent containing Diphtheria (D), Tetanus (T) toxoids, whole cell Pertussis (wP), Hepatitis B (Hep B), type 1, 2, 3 of inactivated poliovirus (IPV) and Haemophilus influenzae type b (Hib) conjugate vaccine (DTwP-HepB-IPV-Hib vaccine, HEXASIIL®) was tested for lot-to-lot consistency and non-inferiority against licensed DTwP-HepB-Hib + IPV in an open label, randomized Phase II/III study. In Phase III part, healthy infants received DTwP-HepB-IPV-Hib or DTwP-HepB-Hib + IPV vaccines at 6, 10 and 14 weeks of age. Blood samples were collected prior to the first dose and 28 days, post dose 3. Non inferiority versus DTwP-HepB-Hib + IPV was demonstrated with 95% CIs for the treatment difference for seroprotection/seroconversion rates. For DTwP-HepB-IPV-Hib lots, limits of 95% CI for post-vaccination geometric mean concentration ratios were within equivalence limits (0.5 and 2). Vaccine was well-tolerated and no safety concerns observed.Clinical Trial Registration - CTRI/2019/11/022052.

Efficacy and Prolonged Safety of Haemophilus influenzae Type b Conjugate Vaccines

OBJECTIVE

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.

METHODOLOGY

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.

RESULT

The search encompassed articles published till now. Subsequently, relevant research papers concerning Haemophilus influenzae meningitis were subjected to a comprehensive review and analysis.

CONCLUSION

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.

A New Role for Old Friends: Effects of Helminth Infections on Vaccine Efficacy

Vaccines are one of the most successful medical inventions to enable the eradication or control of common and fatal diseases. Environmental exposure of hosts, including helminth infections, plays an important role in immune responses to vaccines. Given that helminth infections are among the most common infectious diseases in the world, evaluating vaccine efficiency in helminth-infected populations may provide critical information for selecting optimal vaccination programs. Here, we reviewed the effects of helminth infections on vaccination and its underlying immunological mechanisms, based on findings from human studies and animal models. Moreover, the potential influence of helminth infections on SARS-CoV-2 vaccine was also discussed. Based on these findings, there is an urgent need for anthelmintic treatments to eliminate helminth suppressive impacts on vaccination effectiveness during implementing mass vaccination in parasite endemic areas.

Safety of primary immunization with a DTwP-HBV/Hib vaccine in healthy infants: a prospective, open-label, interventional, phase IV clinical study

OBJECTIVE

This study aimed to assess the safety of a fully liquid DTwP-HBV/Hib pentavalent vaccine (Eupenta^TM) based on the occurrence of adverse events (AEs) following vaccination.

METHODS

This was a prospective, open-label, single-arm, interventional phase IV study. A single intramuscular injection of the study vaccine was administered to infants at approximately 6, 10, and 14 weeks of age, and an end-of-study follow-up visit was scheduled at 18 weeks. Safety data, including immediate reactions, solicited AEs, unsolicited AEs, vital signs, and physical examination findings were collected.

RESULTS

In all, 3000 subjects were enrolled and received at least one dose of the study vaccine. Of these, 2717 (90.6%) experienced at least one AE, most considered related to the study vaccine. Immediate reactions, solicited and unsolicited AEs were respectively identified in 224 (7.5%), 2,652 (88.4%), and 1,099 (36.6%) subjects. The most prevalent solicited and unsolicited AEs comprised pain/tenderness and upper respiratory tract infection, respectively. Most AEs were mildly or moderately severe. Forty-one (1.4%) subjects had at least one serious AE (SAE); of these, two (0.1%) had two SAEs each, considered related to the study vaccine. Six (0.2%) subjects died due to unsolicited AEs, none of which were considered related to the study vaccine. No AEs were reported at the end-of-study follow-up visit.

CONCLUSIONS

The study vaccine administered to infants at 6, 10, and 14 weeks of age had a safety profile similar to that reported in a previous clinical study, and did not result in an increased risk of AEs known to be associated with DTwP-based vaccines or previously unrecognized SAEs.

Surveillance on the adverse events following immunization with the pentavalent vaccine in Zhejiang, China

Objectives

The aim of this study is to describe the reporting rate of adverse events following immunization (AEFI) with pentavalent vaccine: diphtheria-pertussis-tetanus-poliomyelitis-Haemophilus influenzae type b (DPT-IPV/Hib), and to determine whether the reporting rate of AEFI following DPT-IPV/Hib was higher than the average level of the other vaccines.

Methods

Review and describe the AEFI reported to national adverse event following immunization surveillance system (NAEFISS) in Zhejiang province from 2015 to 2020. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR‑1.96SE >1 (standard error [SE]) was considered as positive signal.

Results

NAEFISS received 5726 AEFI reports following DTP-IPV/Hib, with a reporting rate of 20.01/10000 doses. Of the reported AEFI, 202 were serious vaccine product-related reactions, including two cases of anaphylactic shock, five cases of Guillain Barre Syndrome (GBS) and two cases of acute disseminated encephalomyelitis. The reporting rate of fever/redness/induration was the highest among all the clinical diagnosis (14.97/10000 doses). The positive signals were obtained for allergic rash (ROR-1.96SE: 1.36), febrile convulsion (ROR-1.96SE: 1.32) and GBS (ROR-1.96SE: 1.16).

Conclusion

The present findings bolstered that the DTP-IPV/Hib administered as the four-dose schedule was generally well tolerated in Chinese infants as we did not identify any new/unexpected safety concern from the NAEFISS during a six-year timespan.

Influence of schistosomiasis on host vaccine responses

Schistosomiasis is a debilitating helminthiasis which commonly establishes as a chronic infection in people from endemic areas. As a potent modulator of the host immune response, the Schistosoma parasite and its associated products can directly interfere with its host's ability to mount adequate immune responses to unrelated antigens. As a result, increased attention is gathering on studies assessing the influence of helminths, particularly the causal agent of schistosomiasis, on host responsiveness to vaccines. However, to date, no consensus has been drawn regarding the influence of schistosomiasis on host vaccine responses. Here, we review available evidence on the influence of transgenerational and direct Schistosoma parasite exposure on host immune responses to unrelated vaccines. In addition, we evaluate the potential of praziquantel (PZQ) treatment in restoring schistosomiasis-impacted vaccine responses.

Association between maternal literacy and child vaccination in Ethiopia and southeastern India and the moderating role of health workers: a multilevel regression analysis of the Young Lives study

BACKGROUND

Child vaccination coverage in low- and middle-income countries is still far from complete, mainly among marginalized people such as children with illiterate mothers.

OBJECTIVE

This study aims to examine the association between maternal literacy and immunization status of children in Ethiopia and southeastern India (Andhra Pradesh and Telangana) and test whether state-run health centers and community health workers moderate that association.

METHODS

This study is based on cross-sectional data from samples of children in Ethiopia and India, collected as part of round 2 within the Young Lives study (2006). Multilevel logistic regression was conducted to estimate the association between maternal literacy and the completion of four kinds of child vaccinations. We further tested for cross-level interactions between state-run health centers or community health workers and maternal literacy. Estimates were adjusted for several individual- and household-level demographic and socioeconomic factors.

RESULTS

Literate mothers were more likely to complete all four kinds of vaccinations for their children compared to illiterate mothers in Ethiopia (Odds Ratio (OR)=4.84, Confidence Interval (CI)=1.75-13.36). Presence of a health center was positively associated with completed vaccinations in India only (OR = 6.60, CI = 1.57-27.70). A cross-level interaction between community health workers and maternal literacy on the vaccination completion status of children was significant in Ethiopia only (OR = 0.29, CI = 0.09-0.96).

CONCLUSIONS

Our findings suggest that increased availability of community health workers may reduce the child vaccination gap for illiterate mothers, depending on the country context.

Spatial distribution of 12 class B notifiable infectious diseases in China: A retrospective study

BACKGROUND

China is the largest developing country with a relatively developed public health system. To further prevent and eliminate the spread of infectious diseases, China has listed 39 notifiable infectious diseases characterized by wide prevalence or great harm, and classified them into classes A, B, and C, with severity decreasing across classes. Class A diseases have been almost eradicated in China, thus making class B diseases a priority in infectious disease prevention and control. In this retrospective study, we analyze the spatial distribution patterns of 12 class B notifiable infectious diseases that remain active all over China.

METHODS

Global and local Moran's I and corresponding graphic tools are adopted to explore and visualize the global and local spatial distribution of the incidence of the selected epidemics, respectively. Inter-correlations of clustering patterns of each pair of diseases and a cumulative summary of the high/low cluster frequency of the provincial units are also provided by means of figures and maps.

RESULTS

Of the 12 most commonly notifiable class B infectious diseases, viral hepatitis and tuberculosis show high incidence rates and account for more than half of the reported cases. Almost all the diseases, except pertussis, exhibit positive spatial autocorrelation at the provincial level. All diseases feature varying spatial concentrations. Nevertheless, associations exist between spatial distribution patterns, with some provincial units displaying the same type of cluster features for two or more infectious diseases. Overall, high-low (unit with high incidence surrounded by units with high incidence, the same below) and high-high spatial cluster areas tend to be prevalent in the provincial units located in western and southwest China, whereas low-low and low-high spatial cluster areas abound in provincial units in north and east China.

CONCLUSION

Despite the various distribution patterns of 12 class B notifiable infectious diseases, certain similarities between their spatial distributions are present. Substantial evidence is available to support disease-specific, location-specific, and disease-combined interventions. Regarding provinces that show high-high/high-low patterns of multiple diseases, comprehensive interventions targeting different diseases should be established. As to the adjacent provincial units revealing similar patterns, coordinated actions need to be taken across borders.

Structure-based design of chimeric antigens for multivalent protein vaccines

There is an urgent need to develop vaccines against pathogenic bacteria. However, this is often hindered by antigenic diversity and difficulties encountered manufacturing membrane proteins. Here we show how to use structure-based design to develop chimeric antigens (ChAs) for subunit vaccines. ChAs are generated against serogroup B Neisseria meningitidis (MenB), the predominant cause of meningococcal disease in wealthy countries. MenB ChAs exploit factor H binding protein (fHbp) as a molecular scaffold to display the immunogenic VR2 epitope from the integral membrane protein PorA. Structural analyses demonstrate fHbp is correctly folded and the PorA VR2 epitope adopts an immunogenic conformation. In mice, immunisation with ChAs generates fHbp and PorA antibodies that recognise the antigens expressed by clinical MenB isolates; these antibody responses correlate with protection against meningococcal disease. Application of ChAs is therefore a potentially powerful approach to develop multivalent subunit vaccines, which can be tailored to circumvent pathogen diversity.

Factor H binding protein (fHbp) and PorA are components of experimental serogroup B N. meningitidis vaccines. Here the authors graft the VR2 loop of PorA onto an fHBp-based scaffold to demonstrate proof-of-principle of a chimeric antigen strategy and vaccination against meningococcal disease.

Socioeconomic inequality in Hepatitis B vaccination of rural adults in China

Hepatitis B (HB) vaccination is the most effective way to prevent HB virus infection. While measures taken to control the prevalence of HB have achieved significant results, HB prevalence in rural China among adults remains problematic. This study sheds new light on the determinants of HB vaccine uptake and its inequality according to socioeconomic status in rural areas of China. We interviewed 22,283 adults, aged 18-59 years, from 8444 households, in 48 villages from 8 provinces. Vaccination status was modeled by using two logistic models: whether take at least one HB vaccine and whether to complete the entire vaccination regime. The Erreygers' concentration index ([Formula: see text]) was used to quantify the degree of inequality and the decomposition approach was used to uncover the determinants of inequality in vaccine uptake. We found that the coverage rate of HB vaccination is 20.2%, and the completion rate is 16.0%. The [Formula: see text] of at least one dose (0.081) and three doses (0.076) revealed a substantial pro-rich inequality. Income contributed the largest percentage to HB vaccination inequalities (52.17% for at least one dose and 52.03% for complete vaccinations). HB awareness was another important cause of inequality in HB vaccination (around 30%). These results imply that rich had a greater tendency to vaccinate and inequality favouring the rich was almost equal for the complete three doses. While the factors associated with HB vaccination uptake and inequalities were multifaceted, income status and HB awareness were the main barriers for the poor to take HB vaccine by adults in rural China.

A randomized, open-label clinical trial to evaluate immunogenicity and safety of an indigenously developed DTwP-Hib tetravalent combination vaccine (Easyfour®-TT) with Quadrovax® in Indian infants

An open-label, randomized, multi-center trial was conducted to compare the immunogenicity and safety of an indigenously developed tetravalent DTwP-Hib vaccine, Easyfour®-TT with a commercially available vaccine, Quadrovax®. A total of 244 infants in good health, aged 6-10 weeks, were randomized in a 1:1 allocation to receive three doses of the test or comparator vaccine. Immunogenicity of the vaccines was determined by measuring the baseline and post-vaccination antibody response against the vaccine antigens; safety was evaluated in terms of local and systemic reactions (solicited and unsolicited) reported during the trial. Similar levels of seroprotection/seroresponse were achieved, 4 weeks after receiving 3 doses of Easyfour®-TT and Quadrovax®, and the antibody response of Easyfour®-TT was found non-inferior to Quadrovax®, against all four vaccine antigens. Both vaccines were well tolerated and had similar reactogenicity profiles, with a significantly lower occurrence of local (redness at injection site) and systemic reactions (irritability post-vaccination) with Easyfour®-TT vaccine as compared to Quadrovax® (p < 0.05). All adverse events resolved completely with no sequelae. All through the study, only one serious adverse event was observed that completely resolved upon treatment and was deemed unrelated to the vaccine administered. This study demonstrated that Easyfour®-TT vaccine was safe and immunogenic.

CLINICAL TRIAL REGISTRATION NUMBER

CTRI/2014/12/005326 (registered with the Clinical Trial Registry of India (CTRI)).

Adverse events following immunization with pentavalent vaccine: experiences of newly introduced vaccine in Iran

BACKGROUND

The most important factors that affect the incidence of vaccine-related complications are the constituent biological components of the vaccine, injection site reactions, age and sex. The aim of this study is to determine the incidence rate of adverse events following immunization with pentavalent vaccine (DTPw-Hep B-Hib (PRP-T) vaccine (pentavac) (adsorbed) is manufactured by Serum Institute of India ltd), which was introduced in Iran in November 2014. It is important to monitor vaccine-related adverse events because of the role of vaccine safety in immunization program success.

METHODS

This study was a mixed cohort study that included 1119 children less than 1 year of age. In 2015, the children were referred to Hamadan health centers to receive pentavalent vaccine at 2, 4 and 6 months of age. The data were collected from the parents of the children using a questionnaire that was administered either face-to-face or by telephone. The cumulative incidence of side effects and risk ratio was reported with 95% confidence intervals (CI). Chi-squared tests and logistic regressions were used to investigate the association between the variables.

RESULTS

The cumulative incidence rate of pentavalent-related adverse events during 48 h following immunization was estimated to be 15.8% for swelling, 10.9% for redness, 44.2% for pain, 12.6% for mild fever, 0.1% for high fever, 20.0% for drowsiness, 15.0% for loss of appetite, 32.9% for irritability, 4.6% for vomiting and 5.5% for persistent crying. There is no evidence for the occurrence of convulsion and encephalopathy among children who receive pentavalent vaccines.

CONCLUSION

Further large studies with long time follow up are required to address rare events include convulsions, encephalopathy or persistent crying. However, Findings urge immunization programs to use pentavalent vaccinations and to continue implementing the current immunization program in children under 1 year of age.

Budget impact analysis of vaccination against Haemophilus influenzae type b as a part of a Pentavalent vaccine in the childhood immunization schedule of Iran

Background

Health decision makers need to know the impact of the development of a new intervention on the public health and health care costs so that they can plan for economic and financial objectives. The aim of this study was to determine the budget impact of adding Haemophilus influenzae type b (Hib) as a part of a Pentavalent vaccine (Hib-HBV-DTP) to the national childhood immunization schedule of Iran.

Methods

An excel-based model was developed to determine the costs of including the Pentavalent vaccine in the national immunization program (NIP), comparing the present schedule with the previous one (including separate DTP and hepatitis B vaccines). The total annual costs included the cost of vaccination (the vaccine and syringe) and the cost of Hib treatment. The health outcome was the estimated annual cases of the diseases. The net budget impact was the difference in the total annual cost between the two schedules. Uncertainty about the vaccine effectiveness, vaccination coverage, cost of the vaccine, and cost of the diseases were handled through scenario analysis.

Results

The total cost of vaccination during 5 years was $18,060,463 in the previous program and $67,774,786 in the present program. Inclusion of the Pentavalent vaccine would increase the vaccination cost about $49 million, but would save approximately $6 million in the healthcare costs due to reduction of disease cases and treatment costs. The introduction of the Pentavalent vaccine resulted in a net increase in the healthcare budget expenditure across all scenarios from $43.4 million to $50.7 million.

Conclusions

The results of this study showed that the inclusion of the Pentavalent vaccine in the NIP of Iran had a significant impact on the health care budget and increased the financial burden on the government.

Graphical abstract

Budget impact of including Pentavalent vaccine in the national immunization schedule of Iranᅟ

Current trends in hepatitis B vaccination

One of the major successes in the area of vaccinology is the emergence, development and usage of hepatitis B vaccine (a prophylactic vaccine against HBV). Hepatitis B vaccine has protected millions of individuals from acquiring HBV infection and has prevented liver cancer in the majority of vaccinated subjects. Although initially designed as prophylactic vaccines, accumulative evidence has shown that these vaccines may also be used to treat patients with chronic hepatitis B. At present, there are two main areas of discussion in hepatitis B vaccination; development of more effective prophylactic hepatitis B vaccine that can provide protection to all vaccine recipients, and designing hepatitis B-based therapeutic vaccines for treatment of chronic hepatitis B patients.

Future challenges in the elimination of bacterial meningitis

Despite the widespread implementation of several effective vaccines over the past few decades, bacterial meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis and Group B Streptococcus (GBS) still results in unacceptably high levels of human mortality and morbidity. A residual disease burden due to bacterial meningitis is also apparent due to a number of persistent or emerging pathogens, including Mycobacterium tuberculosis, Escherichia coli, Staphylococcus aureus, Salmonella spp. and Streptococcus suis. Here, we review the current status of bacterial meningitis caused by these pathogens, highlighting how past and present vaccination programs have attempted to counter these pathogens. We discuss how improved pathogen surveillance, implementation of current vaccines, and development of novel vaccines may be expected to further reduce bacterial meningitis and related diseases in the future.

Construction of Bordetella pertussis strains with enhanced production of genetically-inactivated Pertussis Toxin and Pertactin by unmarked allelic exchange

Background

Acellular Pertussis vaccines against whooping cough caused by Bordetella pertussis present a much-improved safety profile compared to the original vaccine of killed whole cells. The principal antigen of acellular Pertussis vaccine, Pertussis Toxin (PT), must be chemically inactivated to obtain the corresponding toxoid (PTd). This process, however, results in extensive denaturation of the antigen. The development of acellular Pertussis vaccines containing PTd or recombinant PT (rPT) with inactivated S1, Filamentous Hemagglutinin (FHA), and Pertactin (PRN) has shown that the yield of PRN was limiting, whereas FHA was overproduced. To improve antigen yields and process economics, we have constructed strains of Bordetella pertussis that produce enhanced levels of both rPT and PRN.

Results

Three recombinant strains of Bordetella pertussis were obtained by homologous recombination using an allelic exchange vector, pSS4245. In the first construct, the segment encoding PT subunit S1 was replaced by two mutations (R9K and E129G) that removed PT toxicity and Bp-WWC strain was obtained. In the second construct, a second copy of the whole cluster of PT structural genes containing the above mutations was inserted elsewhere into the chromosome of Bp-WWC and the Bp-WWD strain was obtained. This strain generated increased amounts of rPT (3.77 ± 0.53 μg/mL) compared to Bp-WWC (2.61 ± 0.16 μg/mL) and wild type strain (2.2 μg/mL). In the third construct, a second copy of the prn gene was inserted into the chromosome of Bp-WWD to obtain Bp-WWE. Strain Bp-WWE produced PRN at 4.18 ± 1.02 μg/mL in the cell extract which was about two-fold higher than Bp-WWC (2.48 ± 0.10 μg/mL) and Bp-WWD (2.31 ± 0.17 μg/mL). Purified PTd from Bp-WWD at 0.8-1.6 μg/well did not show any toxicity against Chinese hamster ovary (CHO) cell whereas purified PT from WT demonstrated a cell clustering endpoint at 2.6 pg/well.

Conclusions

We have constructed Bordetella pertussis strains expressing increased amounts of the antigens, rPT or rPT and PRN. Expression of the third antigen, FHA was unchanged (always in excess). These strains will be useful for the manufacture of affordable acellular Pertussis vaccines.

Hepatitis B vaccine effectiveness in the face of global HBV genotype diversity

Recombinant hepatitis B vaccines are of the A2 genotype; one of ten known genotypes whose distribution varies globally. Reports of rare HBV infections in blood donors with an imbalance of non-A2 genotype HBV in vaccinated subjects have raised questions about the cross-protection afforded by HBV-A2 vaccines. Infections in HBV vaccinees were asymptomatic and transient, indicating that vaccination prevented clinical disease. Preclinical data demonstrate cross-reactivity and cross-protection by A2 vaccines against non-A2 HBV genotypes. Substantial improvements in HBV control have been demonstrated in countries with diverse genotype distribution that have introduced universal childhood HBV vaccination programs. Available data show that current HBV-A2 vaccines are highly effective in preventing infections and clinical disease caused by all known HBV genotypes.

Assessment of safety and immunogenicity of two different lots of diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b vaccine manufactured using small and large scale manufacturing process

BACKGROUND

Hib vaccine can be easily incorporated in EPI vaccination schedule as the immunization schedule of Hib is similar to that of DTP vaccine. To meet the global demand of Hib vaccine, SIIL scaled up the Hib conjugate manufacturing process. This study was conducted in Indian infants to assess and compare the immunogenicity and safety of DTwP-HB+Hib (Pentavac(®)) vaccine of SIIL manufactured at large scale with the 'same vaccine' manufactured at a smaller scale.

METHODS

720 infants aged 6-8 weeks were randomized (2:1 ratio) to receive 0.5 ml of Pentavac(®) vaccine from two different lots one produced at scaled up process and the other at a small scale process. Serum samples obtained before and at one month after the 3rd dose of vaccine from both the groups were tested for IgG antibody response by ELISA and compared to assess non-inferiority.

RESULTS

Neither immunological interference nor increased reactogenicity was observed in either of the vaccine groups. All infants developed protective antibody titres to diphtheria, tetanus and Hib disease. For hepatitis B antigen, one child from each group remained sero-negative. The response to pertussis was 88% in large scale group vis-à-vis 87% in small scale group. Non-inferiority was concluded for all five components of the vaccine. No serious adverse event was reported in the study.

CONCLUSIONS

The scale up vaccine achieved comparable response in terms of the safety and immunogenicity to small scale vaccine and therefore can be easily incorporated in the routine childhood vaccination programme.

Primary and booster vaccination in Latin American children with a DTPw-HBV/Hib combination: a randomized controlled trial

BACKGROUND

Diphtheria-tetanus-whole-cell pertussis (DTPw)-based combination vaccines are an attractive option to rapidly achieve high coverage and protection against other important pathogens, such as hepatitis B virus (HBV) and Haemophilus influenzae type B (Hib). To ensure adequate antigen supply, GlaxoSmithKline Biologicals has introduced a new DTPw antigen source and developed a new DTPw-HBV/Hib combination vaccine containing a reduced amount of Hib polyribosylribitol phosphate (PRP). This study was undertaken to compare the immunogenicity and reactogenicity of this new DTPw-HBV/Hib vaccine with a licensed DTPw-HBV/Hib vaccine (Tritanrix™-HBV/Hib).

METHODS

This was a randomized, partially-blind, multicenter study in three countries in Latin America (Argentina, Chile and Nicaragua). Healthy children received either the new DTPw-HBV/Hib vaccine (1 of 3 lots; n = 439; double-blind) or Tritanrix™-HBV/Hib (n = 146; single-blind) co-administered with oral poliovirus vaccine (OPV) at 2, 4 and 6 months, with a booster dose at 18-24 months.

RESULTS

One month after the end of the 3-dose primary vaccination course, the new DTPw-HBV/Hib vaccine was non-inferior to Tritanrix™-HBV/Hib in terms of seroprotection/vaccine response rates for all component antigens; ≥97.3% and ≥93.9% of subjects in the two groups, respectively, had seroprotective levels of antibodies against diphtheria, tetanus, hepatitis B and Hib and a vaccine response to the pertussis component. Persistence of antibodies against all vaccine antigens was comparable between groups, with marked increases in all antibody concentrations after booster administration in both groups. Both vaccines were generally well-tolerated as primary and booster doses.

CONCLUSIONS

Results confirm the suitability of this new DTPw-HBV/Hib vaccine comprising antigens from a new source and a reduced PRP content for inclusion into routine childhood vaccination programs.

TRIAL REGISTRATION

http://www.clinicaltrials.gov NCT00332566.

The immunogenicity and safety of a reduced PRP-content DTPw-HBV/Hib vaccine when administered according to the accelerated EPI schedule

Background

Combination vaccines improve coverage, compliance and effectively introduce new antigens to mass vaccination programmes. This was a phase III, observer-blind, randomized study of GSK Biologicals diphtheria-tetanus-whole cell pertussis vaccine combined with hepatitis B and Haemophilus influenzae type b vaccines, containing a reduced amount of polyribosyl-ribitol-phosphate (PRP) and a DTPw component manufactured at a different site (DTPw-HBV/Hib_2.5 [Kft]). The primary aim of this study was to demonstrate that DTPw-HBV/Hib_2.5 [Kft] was not inferior to the licensed DTPw-HBV/Hib (Tritanrix(tm)-HepB/Hiberix(tm)) vaccine or the DTPw-HBV/Hib_2.5 vaccine, also containing a reduced amount of PRP, with respect to the immune response to the PRP antigen, when administered to healthy infants, according to the Expanded Programme for Immunization (EPI) schedule at 6, 10 and 14 weeks of age.

Methods

299 healthy infants were randomised to receive either DTPw-HBV/Hib_2.5 [Kft] DTPw-HBV/Hib_2.5 or DTPw-HBV/Hib according to the 6-10-14 week EPI schedule. Blood samples were analysed prior to the first dose of study vaccine and one month after the third vaccine dose for the analysis of immune responses. Solicited local and general symptoms such as pain, redness and swelling at the injection site and drowsiness and fever, unsolicited symptoms (defined as any additional adverse event) and serious adverse events (SAEs) were recorded up to 20 weeks of age.

Results

One month after the third vaccine dose, 100% of subjects receiving DTPw-HBV/Hib_2.5 [Kft] or DTPw-HBV/Hib and 98.8% of subjects receiving DTPw-HBV/Hib_2.5 vaccine had seroprotective levels of anti-PRP antibodies (defined as anti-PRP antibody concentration ≥0.15 μg/ml). Seroprotective antibody concentrations were attained in over 98.9% of subjects for diphtheria, tetanus and hepatitis B. The vaccine response rate to pertussis antigen was at least 97.8% in each group. Overall, the DTPw-HBV/Hib_2.5 [Kft] vaccine was well tolerated in healthy infants; no SAEs were reported in any group.

Conclusions

The DTPw-HBV/Hib_2.5 [Kft] vaccine was immunogenic and well-tolerated when administered according to the EPI schedule to Indian infants.

Trial registration

http://www.clinicaltrials.gov NCT00473668

Lipid Nanoparticles with Accessible Nickel as a Vaccine Delivery System for Single and Multiple His-tagged HIV Antigens

Lipid-based nanoparticles (NPs) with a small amount of surface-chelated nickel (Ni-NPs) were developed to easily formulate the human immunodeficiency virus (HIV) his-tagged Tat (his-Tat) protein, as well as to formulate and co-deliver two HIV antigens (his-p24 and his-Nef) on one particle. Female BALB/c mice were immunized by subcutaneous injection with his-Tat/Ni-NP formulation (1.5 μg his-Tat/mouse) and control formulations on day 0 and 14. The day 28 anti-Tat specific immunoglobulin G titer with his-Tat/Ni-NPs was significantly greater than that with Alum/his-Tat. Furthermore, splenocytes from his-Tat/Ni-NP-immunized mice secreted significantly higher IFN-γ than those from mice immunized with Alum/his-Tat. Although Ni-NPs did not show better adjuvant activity than Tat-coated anionic NPs made with sodium dodecyl sulfate (SDS/NPs), they were less toxic than SDS/NPs. The initial results indicated that co-immunization of mice using his-p24/his-Nef/Ni-NP induced greater antibody response compared to using Alum/his-p24/his-Nef. Co-delivery of two antigens using Ni-NPs also increased the immunogenicity of individual antigens compared to delivery of a single antigen by Ni-NPs. In conclusion, Ni-NPs are an efficient delivery system for HIV vaccines including both single antigen delivery and multiple antigen co-delivery.

Immunogenicity of routinely used childhood vaccines when coadministered with the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV)

BACKGROUND

The choice of non-typeable Haemophilus influenzae Protein D as main carrier protein in the candidate 10-valent pneumococcal conjugate vaccine (PHiD-CV, GlaxoSmithKline Biologicals), was driven in part to avoid carrier-mediated suppression and possible bystander interference with coadministered vaccines. Immunogenicity data from 3 primary and 2 booster vaccination studies were assessed for possible impacts of PHiD-CV coadministration on immune responses to routinely administered childhood vaccines, in comparison to 7-valent pneumococcal conjugate vaccine (7vCRM) coadministration.

METHODS

Randomized, controlled studies in which PHiD-CV or 7vCRM vaccines were coadministered with DTPa-[HBV]-IPV/Hib, DTPa-[HBV]-IPV, DTPw-HBV/Hib, IPV, and OPV, combined Hib-Neisseria meningitidis serogroup C vaccine (Hib-MenC-TT), standalone MenC-TT or MenC-CRM vaccines.

RESULTS

One month after primary vaccination, >96% of PHiD-CV recipients had seroprotective antibody concentrations against diphtheria, tetanus, poliovirus types 1 and 3, Hib (>or=0.15 microg/mL), SBA-MenC (>or=1:8), and >94% were seropositive for antibodies against pertussis antigens. Somewhat lower responses against poliovirus type 2 in study A (compared with poliovirus type 1 and 2 responses) and hepatitis B in the 6-, 10-, and 14-week schedule in the Philippines (compared with hepatitis B responses in the other studies) were observed after coadministration of both PHiD-CV and 7vCRM vaccines. Antitetanus and anti-PRP antibody geometric mean concentrations (GMCs) tended to be higher after PHiD-CV coadministration, probably because of the TT carrier protein for serotype 18C in PHiD-CV. Booster vaccination induced substantial increases in antibody GMCs for all coadministered antigens. These responses were generally within the same range in PHiD-CV and 7vCRM groups. Observed anti-PRP responses remained higher in PHiD-CV recipients after the booster dose.

CONCLUSIONS

Coadministration of PHiD-CV with commonly used childhood vaccines induced high levels of seroprotection/seropositivity against all targeted diseases. No evidence of negative interference on the immune response to any of the coadministered vaccine antigens was observed when compared with the current routine practice of 7vCRM coadministration.

The 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) coadministered with DTPw-HBV/Hib and poliovirus vaccines: assessment of immunogenicity

BACKGROUND

Immunogenicity of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was evaluated when coadministered with DTPw-HBV/Hib and OPV at 6, 10, and 14 weeks of age in the Philippines, or with DTPw-HBV/Hib and IPV at 2, 4, and 6 months of age in Poland.

METHODS

In this double-blind, controlled study (107007/NCT00344318), 400 Filipino and 406 Polish infants 6 to 12 weeks of age were randomized (3:1) to receive either PHiD-CV or the 7-valent pneumococcal conjugate vaccine (7vCRM). Immune responses were assessed 1 month post-dose III.

RESULTS

Percentages of infants with anti-pneumococcal antibody concentrations >or=0.2 microg/mL (GSK's 22F-inhibition ELISA) were within the same range for both pneumococcal conjugate vaccine groups, with the exception of serotypes 6B and 23F for which lower percentages were observed in the PHiD-CV group in Poland. At least 98.2% of PHiD-CV vaccinees had antibody concentrations >or=0.2 microg/mL against pneumococcal serotypes 1, 5, and 7F. In both countries, anti-pneumococcal antibody geometric mean concentrations against serotypes 18C and 19F were higher in the PHiD-CV group than in the 7vCRM group. Antibody geometric mean concentrations for most of the other common serotypes were within the same range for both groups in the Philippines and were lower in the PHiD-CV group in Poland. Functional responses (opsonophagocytic activity [OPA]) were observed for all vaccine serotypes in both countries.

CONCLUSIONS

PHiD-CV was immunogenic against each of the 10 pneumococcal vaccine serotypes when coadministered with DTPw-HBV/Hib and poliovirus vaccines.

Clinical experience with DTPw-HBV and DTPw-HBV/Hib combination vaccines

BACKGROUND

Combined diphtheria-tetanus-whole-cell pertussis (DTPw) vaccines remain the cornerstone of many childhood vaccination programs. Larger DTPw-based combination vaccines facilitate high coverage and protection against other childhood pathogens, such as hepatitis B (HBV) and Haemophilus influenzae type b (Hib). Such vaccines have been available since the mid-1990s (Tritanrix-HBV and Tritanrix-HBV/Hib; GlaxoSmithKline [GSK] Biologicals), demonstrating excellent immunogenicity in various schedules. In order to address growing demand for DTPw-based vaccines, GSK Biologicals have developed the Zilbrix range using a new DTPw antigen source and containing reduced quantities of polyribosylribitol phosphate [PRP].

OBJECTIVE

This article presents clinical trial results for both DTPw-based vaccines.

METHODS

GSK Biologicals provided a comprehensive data package, which was supplemented with a Medline literature search.

CONCLUSION

New antigen sources and reduced PRP will ensure the continued supply of DTPw-based combination vaccines for vital global mass vaccination campaigns.

Vaccination greatly reduces disease, disability, death and inequity worldwide

In low-income countries, infectious diseases still account for a large proportion of deaths, highlighting health inequities largely caused by economic differences. Vaccination can cut health-care costs and reduce these inequities. Disease control, elimination or eradication can save billions of US dollars for communities and countries. Vaccines have lowered the incidence of hepatocellular carcinoma and will control cervical cancer. Travellers can be protected against "exotic" diseases by appropriate vaccination. Vaccines are considered indispensable against bioterrorism. They can combat resistance to antibiotics in some pathogens. Noncommunicable diseases, such as ischaemic heart disease, could also be reduced by influenza vaccination. Immunization programmes have improved the primary care infrastructure in developing countries, lowered mortality in childhood and empowered women to better plan their families, with consequent health, social and economic benefits. Vaccination helps economic growth everywhere, because of lower morbidity and mortality. The annual return on investment in vaccination has been calculated to be between 12% and 18%. Vaccination leads to increased life expectancy. Long healthy lives are now recognized as a prerequisite for wealth, and wealth promotes health. Vaccines are thus efficient tools to reduce disparities in wealth and inequities in health.

Vaccination greatly reduces disease, disability, death and inequity worldwide

In low-income countries, infectious diseases still account for a large proportion of deaths, highlighting health inequities largely caused by economic differences. Vaccination can cut health-care costs and reduce these inequities. Disease control, elimination or eradication can save billions of US dollars for communities and countries. Vaccines have lowered the incidence of hepatocellular carcinoma and will control cervical cancer. Travellers can be protected against "exotic" diseases by appropriate vaccination. Vaccines are considered indispensable against bioterrorism. They can combat resistance to antibiotics in some pathogens. Noncommunicable diseases, such as ischaemic heart disease, could also be reduced by influenza vaccination. Immunization programmes have improved the primary care infrastructure in developing countries, lowered mortality in childhood and empowered women to better plan their families, with consequent health, social and economic benefits. Vaccination helps economic growth everywhere, because of lower morbidity and mortality. The annual return on investment in vaccination has been calculated to be between 12% and 18%. Vaccination leads to increased life expectancy. Long healthy lives are now recognized as a prerequisite for wealth, and wealth promotes health. Vaccines are thus efficient tools to reduce disparities in wealth and inequities in health.

Primary vaccination with a new heptavalent DTPw–HBV/Hib–Neisseria meningitidis serogroups A and C combined vaccine is well tolerated

OBJECTIVE

Safety and reactogenicity of a new heptavalent DTPw-HBV/Hib-MenAC (diphtheria, tetanus, whole cell pertussis-hepatitis B virus/Haemophilus influenzae type b-Neisseria meningitidis serogroups A and C) vaccine was compared with a widely used pentavalent DTPw-HBV/Hib vaccine.

METHODS

Three phase III randomized studies comparable in design and methodology, in which healthy infants received DTPw-HBV/Hib-MenAC (N=1334) or DTPw-HBV/Hib (N=446) at 2, 4, and 6 months, were pooled for analysis. Solicited symptoms were recorded for 4 days, and unsolicited adverse events for 31 days after each dose. Serious adverse events (SAEs) were recorded throughout the studies.

RESULTS

There were no significant differences between the two groups in the proportion of subjects with fever >39.5 degrees C or >40.0 degrees C (p<0.005). Compared to group DTPw-HBV/Hib, a significantly higher percentage of subjects in group DTPw-HBV/Hib-MenAC reported fever >39 degrees C (21.2% vs. 14.8%, p=0.004). Fever subsided quickly, did not lead to differences in attendance to medical services and did not increase from dose to dose. Sixty-seven SAEs were reported, 56/1334 (4.2%) in group DTPw-HBV/Hib-MenAC and 11/446 (2.5%) in the DTPw-HBV/Hib group.

CONCLUSION

Overall, the heptavalent and pentavalent vaccines had similar safety profiles. The difference observed in percentage of subjects with fever >39 degrees C did not lead to differences in medically attended visits for fever.

Safety monitoring of a new pentavalent vaccine in the expanded programme on immunisation in Ghana

BACKGROUND AND OBJECTIVE

Safety monitoring of vaccines used in expanded programmes on immunisation is important in all countries, including those with limited resources. As the rates of target diseases decrease, parents become less accepting of even minor common adverse events. Identification, detection, prevention and appropriate communication of adverse events following immunisation (AEFI) are therefore essential to preserve the integrity of immunisation programmes and protect public health. The objective of this study was to document the occurrence of common minor AEFI associated with a newly introduced pentavalent vaccine for routine immunisation in Ghana's expanded programme on immunisation.

METHODS

A prospective descriptive study on AEFI associated with the administration of a pentavalent diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type B (DTP-hepatitis B vaccine/Hib vaccine) vaccine that is part of the Expanded Programme on Immunisation was carried out in four locations in Accra, Ghana. These locations were the nation's premier teaching hospital (the Korle-Bu Teaching Hospital) two urban polyclinics (the Mamprobi and Ussher Town polyclinics) and a community immunisation centre (the Zongo Junction Immunisation Centre).A total of 406 infants were recruited for the study. Upon receipt of signed informed consent from the parents/guardians of the infants, the parents/guardians were supplied with a pink card that functioned as a pseudo-diary for recording AEFI that occurred at home and for measuring and noting the sizes of any injection-site swellings that might occur. It also enabled each participant to obtain free medical care at the Department of Child Health, Korle-Bu Teaching Hospital for the duration of the study (from September 2003 to December 2004) and until the child was 12 months old. Information about the occurrence of AEFI was actively solicited during each visit for immunisation and also at a visit 4 weeks after administration of the last dose of pentavalent vaccine, when participants were asked to report to the respective immunisation centres for the specific purpose of reporting any AEFI which might have occurred in the intervening period. These AEFI were analysed separately from those reported to the dedicated hospital unit at the Department of Child Health, Korle-Bu Teaching Hospital, since the AEFI reported to that unit were all verified and recorded by trained physicians.

RESULTS

Of the 406 infants, 368 completed the study, whereas 38 defaulted or were lost to follow-up. There were 104 attendances to report cases of suspected AEFI requiring physician attention at the Department of Child Health, Korle-Bu Teaching Hospital. These attendances were made by 74 patients who reported 190 events; notable among these were cough (26.3% of all AEFI reported to the hospital), fever (17.4%), common cold (12.1%), vomiting (7.4%) and diarrhoea (6.8%). Three of these visits involved AEFI that were classified as 'serious', since they required hospitalisation, but all three were considered to be unlikely to be related to vaccine administration. In addition, actively solicited information on AEFI following immunisation from 921 individual interviews with the parents/guardians of immunised infants during the follow-up visits resulted in reports of 259 events being reported, the most common, according to crude incidence rates, being fever (14.7%), common cold (3.8%), crying (3%) and cough (2.8%).

CONCLUSION

The results of this study show agreement with safety studies on vaccines containing identical or similar antigens performed elsewhere and indicate the safety and tolerability of the pentavalent DTP-hepatitis B vaccine/Hib vaccine in Ghanaian children.

Should hepatitis B vaccination be introduced into childhood immunisation programmes in northern Europe?

Infection with hepatitis B causes between 500,000 and 1.2 million deaths per year worldwide, and is the leading cause of liver cancer. Over 12 years ago, WHO recommended that universal childhood hepatitis B vaccination be implemented globally. Despite this, Denmark, Finland, Iceland, Ireland, the Netherlands, Norway, Sweden, and the UK have yet to implement such a policy and instead currently adopt an "at-risk" strategy. Although all eight countries are classed as having low endemicity, factors such as increased travel and integration of immigrant communities are increasing the number of at-risk individuals in these countries. Considering the difficulty in identifying all at-risk individuals, and the lack of effectiveness of at-risk vaccination on reducing the overall incidence of hepatitis B, we recommend that these countries reassess their hepatitis B prevention strategies. Universal vaccination against hepatitis B is the only way to eliminate the major public-health impact of this disease.

Coadsorption of HIV-1 p24 and gp120 proteins to surfactant-free anionic PLA nanoparticles preserves antigenicity and immunogenicity

Biodegradable micro- or nanoparticles with surface adsorbed antigens represent a promising method for in vivo delivery of vaccines. Most vaccines, licensed or under development, are based on combined delivery of multiple antigens. Thus, we investigated the feasibility of combining two vaccine antigens, HIV-1 p24 and gp120 proteins, on the surface of surfactant-free anionic PLA nanoparticles obtained by an improved solvent diffusion method. The analysis of adsorption isotherms has shown that both proteins had similar and high affinities for the nanoparticles. Coadsorption of p24 and gp120 onto the same PLA particle was evidenced by sandwich ELISA, using antibodies directed against one protein for particle capture and the other one for detection. To assess structural integrity, the antigenicity of free and PLA-adsorbed antigens was compared by competition ELISA, using a set of 6 anti-p24 and 7 anti-gp120 antibodies, as well as soluble CD4. The antigenicity of proteins on the nanoparticle surface was well preserved, adsorbed either individually or in combination. Furthermore, both antigens maintained their immunogenicity, since high antibody titres (10(6) for p24 and 10(5) for gp120) were elicited in mice with monovalent and divalent PLA formulations. Taken together our results show that development of multivalent vaccines based on anionic PLA nanoparticles is possible. Moreover, coadsorption of a ligand for cell-specific targeting or of an immunostimulatory molecule will further extend the field of application of delivery systems based on charged micro- and nanoparticles.

Reactogenicity and immunogenicity profiles of a novel pentavalent diphtheria-tetanus-whole cell pertussis-hepatitis B and Haemophilus influenzae type B vaccine: a randomized dose-ranging trial of the Hib tetanus-conjugate content

BACKGROUND

Combined vaccines containing diphtheria-tetanus-pertussis whole-cell (DTPw), Haemophilus influenzae type b (Hib), and hepatitis-B vaccines are essential for the continuing success of vaccination programs in developing nations. This randomized, dose-ranging study assessed the immunogenicity and reactogenicity of primary and booster vaccination with pentavalent DTPw-HBV/Hib vaccines containing 10, 5 or 2.5 microg of polyribosylribitol phosphate (PRP) conjugated to tetanus toxoid (trials Hib-052/064).

METHODS

Six hundred eighty infants were randomized to receive one of 5 vaccine combinations at 6, 10, and 14 weeks of age. Of these, 351 received the same vaccine at 15-24 months of age. The immune response was evaluated on blood samples collected 1 month after the 3-dose primary course and before and 6 weeks after the booster dose. Reactogenicity was assessed during a 4-day period after each vaccine dose using diary cards.

RESULTS

After primary vaccination, all subjects had seroprotective anti-PRP antibody concentrations (> or = 0.15 microg/mL) and > 95% had concentrations > or = 1.0 microg/mL, irrespective of the PRP dose administered. Anti-PRP antibody avidity after primary vaccination and antibody persistence until the second year of life were similar among groups. The booster dose induced marked increases in anti-PRP antibody GMCs and antibody avidity, indicative of effective priming and the presence of immune memory. All vaccination regimens elicited good immune responses and comparable antibody persistence to the other vaccine antigens, with significant increases in all antibody concentrations observed after boosting. All vaccination regimens were safe, with similar overall reactogenicity profiles.

CONCLUSION

Hib conjugate vaccines containing reduced amounts of PRP can be effectively combined with the licensed DTPw-HBV vaccine to provide protection against 5 major childhood pathogens in a single injection.

Is there a need for a new generation of vaccines against pertussis?

Current vaccines against pertussis have proved their safety and efficacy in large-scale clinical trials. Despite high vaccination coverage, pertussis is still prevalent and increasing, probably as a result of waning immunity. Addition of new antigens, such as adenylate cyclase, to current vaccines might improve some aspects of the immune response to vaccination, but are unlikely to significantly increase the duration of protection. Intranasal, oral and DNA pertussis vaccines are some way from clinical development, although one live attenuated, intranasal pertussis vaccine may soon enter Phase I trials. In the meantime, the potential of currently available safe and efficacious pertussis vaccines should be maximised. Rationalisation of pertussis boosters in childhood and introduction of widespread repeat booster vaccination in adolescents and adults would already lessen disease prevalence and morbidity among susceptible infants.