Vial usage, device dead space, vaccine wastage, and dose accuracy of intradermal delivery devices for inactivated poliovirus vaccine (IPV)

Evaluation of luciferase and prefusion-stabilized F protein from respiratory syncytial virus mRNA/LNPs in pre-clinical models using jet delivery compared to needle and syringe

Described here is the evaluation of a luciferase (luc) and respiratory syncytial virus (RSV) messenger RNA / lipid nanoparticle (mRNA/LNP) vaccine using a Needle-free Injection System, Tropis®, from PharmaJet® (Golden, Colorado USA). Needle-free jet delivery offers an alternative to needle/syringe. To perform this assessment, compatibility studies with Tropis were first performed with a luc mRNA/LNP and compared to needle/syringe. Although minor changes in particle size and encapsulation efficiency were observed when using Tropis on the benchtop, in vitro luciferase activity remained the same. Next, the luc mRNA/LNP was administered to rats intramuscularly using Tropis or needle/syringe and tracking of the injection and distribution was performed. Lastly, an mRNA encoding a prefusion-stabilized F protein from RSV was delivered intramuscularly using both Tropis and needle/syringe at 1 and 5 mcg mRNA. An equivalent IgG response was observed using both Tropis and needle/syringe. The cell mediated immune (CMI) response was also evaluated, and responses to RSV-F were detected from animals immunized with needle/syringe at all dose levels, and from the animals immunized with Tropis in the 5 and 25 ug groups. These results indicated that delivery of mRNA/LNPs with Tropis is a potential means of administration and an alternative to needle/syringe.

Accuracy, Precision, and Residual Volume of Commonly Used Syringes for Intravitreal Injections and the Impact on Intraocular Pressure

PURPOSE

To compare accuracy, precision, and residual volume of commonly used syringes for intravitreal injections (IVIs) and to assess the intraocular pressure (IOP) rise by variations in volumes delivered.

DESIGN

Experimental laboratory study.

SUBJECTS

No subjects were involved in this study.

METHODS

We tested 8 syringe models with 2 different needle setups, with 2 different solutions (distilled water or glycerin) and target volumes (50 and 70 μL). To obtain the delivered and residual volumes, we weighed the syringe-needle setups with scale before liquid withdrawal, with liquid, and after liquid release. We also created an experimental eye model to determine the transient rise in IOP following stepwise 10-μL increases in injection volumes.

MAIN OUTCOME MEASURES

Delivered and residual volumes, IOP rise.

RESULTS

We tested a total of 600 syringe-needle setups. Becton Dickinson (BD) Ultra-Fine (0.34 ± 0.28 μL), Zero Residual (1.53 ± 1.15 μL), and Zero Residual Silicone Oil-free (1.40 ± 1.16 μL) syringes showed the lowest residual volume (P < 0.001) in comparison with the others (range: 24.86 ± 1.78 μL for Injekt-F to 51.97 ± 3.37 μL for Omnifix-F). The most accurate setups were (percentage deviation from target volume): Zero Residual Silicone Oil-free (+ 0.70%), Zero Residual 0.3 ml (+ 4.49%), BD Ultra-Fine (+ 7.83%), Injekt-F (9.42%), Norm-Ject (+ 15.88%), Omnifix-F (+ 16.96%), BD Plastipak Brazil (+17.96%), and BD Plastipak Spain syringes (+ 19.41%). There was a statistically significant difference between the Zero Residual Silicone Oil-free syringe and all other syringes (P < 0.0001), except for the Zero Residual 0.3-ml syringe (P = 0.029). The coefficient of variation was low for all syringes. The modeled IOP rise ranged from 32.3 (standard deviation [SD], 1.4) mmHg for 20-μL injection volume to 76.5 (SD, 1.0) mmHg for 80-μL injection volume. For the standard 50-μL injection volume, the peak pressure was 50.7 (SD, 0.1) mmHg, and the pressure rise duration was 28 (SD, 2) minutes.

CONCLUSIONS

There were significant differences in accuracy and residual volume between syringes, whereas they showed a high precision. Volume excess results in a considerable increase in IOP rise after injection. These findings may provide a relevant overview to clinicians and to both device and drug manufacturers regarding pharmacoeconomic, safety, and efficacy issues.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Understanding the Relationship between Vaccine Supply Dead Space and Wasted COVID-19 Vaccine Doses

INTRODUCTION

By July 2023, Brazil had administered approximately 540 million COVID-19 vaccine doses. This study aimed to quantify wasted doses resulting from dead space in vaccine supplies.

METHODS

The vaccine supply was initially weighed, filled with distilled water, and expelled to simulate administration. Weighing it again after the application determined the dead space volume. Descriptive analyses calculated the waste rate/wasted dose count.

RESULTS

The estimated total number of wasted vaccine doses using supplies with the lowest dead space was 62,097,338.

CONCLUSIONS

Syringe dead space is a crucial factor in dose wastage, directly influencing the number of wasted doses.

Immune Response of Inactivated Rabies Vaccine Inoculated via Intraperitoneal, Intramuscular, Subcutaneous and Needle-Free Injection Technology-Based Intradermal Routes in Mice

Inoculation routes may significantly affect vaccine performance due to the local microenvironment, antigen localization and presentation, and, therefore, final immune responses. In this study, we conducted a head-to-head comparison of immune response and safety of inactivated rabies vaccine inoculated via intraperitoneal (IP), intramuscular (IM), subcutaneous (SC) and needle-free injection technology-based intradermal (ID) routes in ICR mice. Immune response was assessed in terms of antigen-specific antibodies, antibody subtypes and neutralizing antibodies for up to 28 weeks. A live rabies virus challenge was also carried out to evaluate vaccine potency. The dynamics of inflammatory cell infiltration at the skin and muscle levels were determined via histopathological examination. The kinetics and distribution of a model antigen were also determined by using in vivo fluorescence imaging. Evidence is presented that the vaccine inoculated via the ID route resulted in the highest antigen-specific antibody and neutralizing antibody titers among all administration routes, while IP and IM routes were comparable, followed by the SC route. Antibody subtype analysis shows that the IP route elicited a Th1-biased immune response, while SC and IM administration elicited a prominent Th2-type immune response. Unexpectedly, the ID route leads to a balanced Th1 and Th2 immune response. In addition, the ID route conferred effective protection against lethal challenge with 40 LD50 of the rabies CVS strain, which was followed by IP and IM routes. Moreover, a one-third dose of the vaccine inoculated via the ID route provided comparable or higher efficacy to a full dose of the vaccine via the other three routes. The superior performance of ID inoculation over other routes is related to longer local retention at injection sites and higher lymphatic drainage. Histopathology examination reveals a transient inflammatory cell infiltration at ID and IM injection sites which peaked at 48 h and 24 h, respectively, after immunization, with all side effects disappearing within one week. These results suggest that needle-free injection technology-based ID inoculation is a promising strategy for rabies vaccination in regard to safety and efficacy.

Preclinical evaluation of performance, safety and usability of VAX-ID®, a novel intradermal injection device

The recent SARS-Cov2 pandemic and mpox health emergency have led to renewed interest in intradermal vaccination due to its dose sparing potential. Indeed, intradermal vaccination is particularly of interest for use in mass vaccination campaigns, pandemic preparedness programs, and/or for vaccines that are expensive or in short supply. Moreover, the rich immune network in the skin makes it an attractive target not only for prophylactic vaccination, but also for therapeutic vaccination, like immunotherapy and (dendritic) cell-based therapies. The aim of the current paper was to provide an overview of preclinical data generated with VAX-ID®, a novel intradermal drug delivery device, to allow assessing it performance, safety and usability. The device can overcome challenges seen with the Mantoux technique whereby the needle needs to be inserted under a shallow angle. Various parameters of VAX-ID® were evaluated, including dead-space volume, dose accuracy, penetration depth & liquid deposit in piglets, as well as usability by healthcare professionals. The device has shown to have a low dead volume and a high dose accuracy. Importantly, the device performed successful injections at a predefined depth into the dermis with a high safety profile as confirmed by visual and histological evaluation in piglets. Moreover, the device was rated as easy to use by healthcare professionals. The combined preclinical performance and usability findings indicate that VAX-ID® can provide reliable, standardized and accurate drug delivery in the dermal layer of the skin with a high ease of use. The device offers a solution for injection of various prophylactic as well as therapeutic vaccines.

An analysis of the effect of syringe barrel volume on performance and user perception

In the market, there are many types and shapes of syringes. One of the groupings of syringe types is based on barrel volume. The shape of the product design affects performance and user perception. The aim of this study is to investigate the effect of barrel volume on its performance and user perception. We performed analysis following international organization for standardization 7886 procedures on syringe with 1 mL, 3 mL, 5 mL, and 10 mL volume. In addition, a user perception test was conducted on 29 respondents using a questionnaire with the Likert chart method. This study indicates that the bigger the syringe volume, the larger the dead space and the force to operate the piston are. A larger syringe volume also raises the volume that changes due to the plunger position increase. Meanwhile, the barrel volume does not affect water and water leakage, as we did not observe any leak during the syringe tests in our experiment. In addition, the user perception test shows that the barrel's length influences the ease of device control during the injection. The volume of the barrel negatively correlated with its effect to the environment. The safety features of all syringes are similar except for the 3 mL syringe, which has a value of 0.1 points difference to other syringes.

Respiratory Syncytial Virus (RSV) Disease and Prevention Products: Knowledge, Attitudes, and Preferences of Kenyan Healthcare Workers in Two Counties in 2021

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection (LRTI) among infants under 6 months of age. Yet, in Kenya, little is known about healthcare workers' (HCWs) knowledge, attitudes, and perceptions around RSV disease and the prevention products under development. Between September and October 2021, we conducted a mixed methods cross-sectional survey to assess HCWs' knowledge, attitudes, and perceptions of RSV disease and RSV vaccinations in two counties. We enrolled HCWs delivering services directly at maternal and child health (MCH) departments in selected health facilities (frontline HCWs) and health management officers (HMOs). Of the 106 respondents, 94 (88.7%) were frontline HCWs, while 12 were HMOs. Two of the HMOs were members of the Kenya National Immunization Technical Advisory Group (KENITAG). Of the 104 non-KENITAG HCWs, only 41 (39.4%) had heard about RSV disease, and 38/41 (92.7%) felt that pregnant women should be vaccinated against RSV. Most participants would recommend a single-dose vaccine schedule (n = 62, 58.5%) for maximal adherence and compliance (n = 38/62, 61.3%), single dose/device vaccines (n = 50/86, 58.1%) to prevent wastage and contamination, and maternal vaccination through antenatal care clinics (n = 53, 50%). We found the need for increased knowledge about RSV disease and prevention among Kenyan HCWs.

Dose-sparing effect of Sabin-derived inactivated polio vaccine produced in Japan by intradermal injection device for rats

The live-attenuated oral polio vaccine has long been used as the standard for polio prevention, but in order to minimize the emergence of pathogenic revertants, the inactivated polio vaccine (IPV), which is administered intramuscularly or subcutaneously, is being increasingly demanded worldwide. However, there is a global shortage of IPV, and its cost is an obstacle in developing countries. Therefore, dose-sparing with intradermal administration of IPV has been investigated. In this study, rats were immunized by intradermal (ID) and intramuscular (IM) administration of Sabin-derived inactivated polio vaccine (sIPV) produced in Japan, and the immune responses were evaluated. The results showed that one-fifth (1/5)-dose of ID administration yielded neutralizing antibody titers comparable to the full-dose IM administration, whereas 1/5-dose of IM administration was less effective than the full dose. Furthermore, a vertical puncture-type ID injection device (Immucise) that was originally developed for humans was modified for rats, resulting in successful and stable ID administration into the thin skin of rats. Based on these results, the ID administration of sIPV using Immucise in clinical use is expected to offer benefits such as reduced amounts of vaccine per dose, cost-effectiveness, and thereby the feasibility of vaccination for more people.

Improved DNA Vaccine Delivery with Needle-Free Injection Systems

DNA vaccines have inherent advantages compared to other vaccine types, including safety, rapid design and construction, ease and speed to manufacture, and thermostability. However, a major drawback of candidate DNA vaccines delivered by needle and syringe is the poor immunogenicity associated with inefficient cellular uptake of the DNA. This uptake is essential because the target vaccine antigen is produced within cells and then presented to the immune system. Multiple techniques have been employed to boost the immunogenicity and protective efficacy of DNA vaccines, including physical delivery methods, molecular and traditional adjuvants, and genetic sequence enhancements. Needle-free injection systems (NFIS) are an attractive alternative due to the induction of potent immunogenicity, enhanced protective efficacy, and elimination of needles. These advantages led to a milestone achievement in the field with the approval for Restricted Use in Emergency Situation of a DNA vaccine against COVID-19, delivered exclusively with NFIS. In this review, we discuss physical delivery methods for DNA vaccines with an emphasis on commercially available NFIS and their resulting safety, immunogenic effectiveness, and protective efficacy. As is discussed, prophylactic DNA vaccines delivered by NFIS tend to induce non-inferior immunogenicity to electroporation and enhanced responses compared to needle and syringe.

The hypodermic syringe performance based on the ISO 7886-1:2017: A narrative review

A syringe is used to inject fluid or medicine into the patient's soft tissue. The main components of the syringe were the needle, barrel, and plunger. The use of syringes in the medical world is relatively high, and especially since the COVID-19 pandemic, the use of hypodermic syringes increased sharply due to vaccination. The syringe used must be effective and of good quality, so the International Organization for Standardization (ISO) has published test procedures and minimum specifications for hypodermic syringes. The performance of the syringe can be observed from the dead space, force piston operation, water and air leakage, and fitting position of the plunger in the barrel. This review shows that most researchers use the weighing method to measure the dead space, although some use other methods. The researchers found that most of the products met the minimum specifications of the ISO, and that the dimensions and shape of the syringe affected the dead space. Researchers have not examined other performance measures recommended by the ISO. Researchers have focused more on force injection than force piston operation, leakage after injection or back spray than air and water leakage, and reduction the friction of the plunger without considering the fitting position of the plunger in the barrel.

Performance and usability evaluation of novel intradermal injection device Immucise™ and reanalysis of intradermal administration trials of influenza vaccine for the elderly

Under the pandemic situation, there is an urgent need to produce and acquire sufficient quantities of prophylactic vaccines. It becomes important to devise a way to achieve reliable immunity with lower doses to distribute limited supplies of vaccines to maximum number of people very quickly. Intradermal (ID) vaccination is one such method to increase the effectiveness of vaccines. However, this method has not been widely used in general clinical practice because it is technically difficult to inject vaccines precisely into the ID tissue. Therefore, new ID delivery systems that allow reliable ID administration are under development. In this paper, we summarize its design and present the results of performance and usability testing for the Immucise™ Intradermal Injection System (Immucise™). This study showed that Immucise™ can reduce dead volume and inject drugs precisely into the ID tissues of subjects from infants to the elderly and can be used correctly and safely by healthcare professionals. This randomized controlled trial compared ID administration with Immucise™ and standard subcutaneous (SC) administration of seasonal influenza vaccine by analyzing the efficacy of the vaccine in the elderly group at 90 days and 180 days after administration. It was found that the vaccine for the ID group was as effective or more effective than that for the SC group up to 180 days later. It was also found that the geometric mean titer values, especially for B strains, were higher in the two-dose ID group than in the two-dose SC group. These findings suggest that Immucise™ is one of the best devices to distribute a small amount of vaccine quickly and widely to a larger number of people with little loss of vaccine during a pandemic.

Microneedle-mediated transdermal nanodelivery systems: a review

The greatest limitation in the development of transdermal drug delivery systems is that only a few drugs can permeate the skin due to the barrier function of the stratum corneum. Active and passive methods are generally available for improving the ability of drug transdermal delivery. However, nanoparticles, as a passive approach, exhibit capacity-constrained permeation enhancement. Thus, microneedle-mediated nanoparticles possess enormous potential and broad prospects. Microneedles promote the penetration of macromolecules by creating microchannels on the skin surface. In this review, the prevailing subknowledge on microneedles (mechanism, classification, and applications of microneedles combined with nanoparticles) is discussed to provide a guideline for readers and a basic reference for further in-depth studies of this novel drug delivery system.

A fuzzy multi-criteria framework to identify barriers and enablers of the next-generation vaccine supply chain

Purpose

Due to the introduction of new vaccines in the child immunization program and inefficient vaccine supply chain (VSC), the universal immunization program (UIP), India is struggling to provide a full schedule of vaccination to the targeted children. In this paper, the authors investigate the critical factors for improving the performance of the existing VSC system by implementing the next-generation vaccine supply chain (NGVSC) in India.

Design/methodology/approach

The authors design a fuzzy multi-criteria framework using a fuzzy analytical hierarchical process (FAHP) and fuzzy multi-objective optimization on the basis of ratio analysis (FMOORA) to identify and analyze the critical barriers and enablers for the implementation of NGVSC. Further, the authors carry out a numerical simulation to validate the model.

Findings

The outcome of the analysis contends that demand forecasting is the topmost supply chain barrier and sustainable financing is the most important/critical enabler to facilitate the implementation of the NGVSC. In addition, the simulation reveals that the results of the study are reliable.

Social implications

The findings of the study can be useful for the child immunization policymakers of India and other developing countries to design appropriate strategies for improving existing VSC performance by implementing the NGVSC.

Originality/value

To the best of the authors’ knowledge, the study is the first empirical study to propose the improvement of VSC performance by designing the NGVSC.

A multipurpose brachytherapy catheter to enable intratumoral injection

PURPOSE

To create and test a multipurpose brachytherapy catheter prototype enabling intratumoral injection and brachytherapy after a single catheter insertion.

METHODS AND MATERIALS

The design of the prototype consists of an outer tube and an inner syringe tube that can be filled with injectable agent. The outer sheath and inner syringe tube were constructed using polytetrafluoroethylene tubing, and the other components were 3D printed using dental resin and polylactic acid material. To demonstrate functionality, we injected in vitro phantoms with dyed saline. For proof of concept, we demonstrated the potential for the prototype to deliver cell therapy, enhance tumor delineation, deliver tattoo ink for pathology marking, avoid toxicity through local delivery of chemotherapy, and facilitate combination brachytherapy and immunotherapy.

RESULTS

The prototype enables accurate injection in vitro and in vivo without altering dosimetry. To illustrate the potential for delivery of cell therapies, we injected luciferase-expressing splenocytes and confirmed their delivery with bioluminescence imaging. To demonstrate feasibility of radiographically visualizing injected material, we delivered iohexol contrast intratumorally and confirmed tumor retention using Faxitron x-ray imaging. In addition, we show the potential of intratumoral administration to reduce toxicity associated with cyclophosphamide compared with systemic administration. To demonstrate feasibility, we treated tumor-bearing mice with brachytherapy (¹⁹²Ir source, 2 Gy to 5 mm) in combination with intratumoral injection of 375,000 U of interleukin 2 and observed no increased toxicity.

CONCLUSIONS

These results demonstrate that a prototype multipurpose brachytherapy catheter enables accurate intratumoral injection and support the feasibility of combining intratumoral injection with brachytherapy.

The Association between Needle Size and Waste Product and Its Effect on Cost-Effectiveness of Botulinum Toxin Injections?

Clostridium botulinum toxin (BT) must be administered intramuscularly with a syringe, but dead space in the syringe–needle complex may cause product waste and result in cost implications for the patient and provider. Syringe dead space is the volume of residual fluid that remains within the syringe after the plunger is fully depressed during medication injection. We calculated the average volume of remaining product in a syringe–needle complex and cost loss implication of this volume of BT. This is a single-center, analytical study using saline and four different sized needles for analytics of waste product and cost-effectiveness. Syringes of 1 mL with attached 18, 21, 30, and 32-gauge (G) needles, respectively, were compared. The syringe–needle complex was weighed before drawing 0.05 mL of saline. The fluid was then discarded with the appropriate syringe and then weighed again. This procedure was repeated for the four needle types and the average difference in weight of the syringe–needle complex before and after saline waste was measured. The volume was converted to units of BT used in clinical practice and the cost of waste product evaluated. The mean difference in needle–syringe complex weight before and after intervention was 0.068, 0.056, 0.04, and 0.026 g for the 18, 21, 30, and 32G needles, respectively. We found a statistically significant difference comparing the 18G with the 30 and 32G (0.02 and 0.0007, respectively) and comparing the 21G with the 30 and 32G (0.0042 and 0.00002, respectively). When we extrapolated the data to BT units (4U/0.1 mL), we found that theoretically 2.72, 2.24, 1.6, and 1.04 units of BT are left in the syringe–needle complex for the 18, 21, 30, and 32G syringes, respectively. At a cost of $6.01/U of onabotulinum toxin A, we then calculated a provider loss of a gross average (mean) revenue of $96 and 62.4 per 10 syringes used with 30 and 32G needles. Needle size used for drawing up and administering BT has an effect on the amount of waste product and subsequently on cost-effectiveness.

Estimation of the wastage rate of MMR and pentavalent vaccines in open and closed vials in three western provinces of Iran

Background

Vaccine wastage is one of quality indicators of immunization program and high vaccine wastage will increase overall costs and impede efforts towards a more efficient and sustainable program. We aimed at estimating of the wastage rates of Measles-Mumps-Rubella (MMR) and pentavalent (diphtheria-tetanus-pertussis-hepatitis B -Haemophilus influenza type b) vaccines in different vaccine vial sizes.

Study design

Multicentre descriptive study using existing data.

Methods

This study was in three provinces (Hamadan, Kermanshah and Kordestan) of Iran including 131,135 populations with 2,548 under-1years children. Twenty-seven health facilities were selected randomly from nine districts in three provinces of western part of Iran. Six-months data including vaccination and vaccine stock records collected from April to September 2017. Finally, number of opened vials and number of target population vaccinated were collected and data were analysed to estimate the wastage rates in both unopened and opened vials of both antigens.

Results

The wastage rate for combined MMR 2-dose and 5-dose opened vials for three provinces was 29%(Hamadan 18%, Kermanshah 14% and Kordestan 52%). The wastage rate for combined pentavalent single-dose and 10-dose vials for three provinces was 17% (in Kordestan33%, 11% Kermanshah 11% and Hamedan 3%). The total average of pentavalent single-dose and 10-dose vials wastage rate was 5% and varied 13% for urban and 3% for rural areas. The average of discarded unopened vials wastage rate in all facilities for MMR was 3.9% (3.2% for MMR 2-dose vial and 10.2% for MMR 5-dose vial). This rate was 1.7% for pentavalent total (1.9% for single dose vial and 0.4% for 10 dose vial).

Conclusion

The vaccine wastage rates in Iran are in line with other countries and lower than the suggested rate based on WHO policies for multi-dose vials. The wastage rates were different for in provinces, districts and health facilities. The MMR total wastage rate in rural is higher than those in urban areas. However, the pentavalent total wastage rate was higher in urban area.

Prioritizing the vaccine supply chain issues of developing countries using an integrated ISM-fuzzy ANP framework

Purpose

Delivering vaccines to the children who need them requires a supply chain that is efficient and effective. In most of the developing countries, however, the unknown and unresolved supply chain issues are causing inefficiencies in distributing vaccines. There is, therefore, a great need in such countries to recognize the issues that cause delays in vaccine delivery. With this purpose, the present study aims to identify and analyze the key issues in the supply chain of basic vaccines required to immunize children in developing countries.

Design/methodology/approach

Based on a field survey of three states of India, in-depth review of relevant literature and experts’ opinions, 25 key issues were recognized as factors of the vaccine supply chain (VSC) and categorized into five main domains. Using integrated interpretive structural modeling and fuzzy analytic network process approaches, the issues have been prioritized to determine their relative importance in the VSC. In addition, a sensitivity analysis has been performed to investigate the priority stability of the issues.

Findings

The results of the analysis show that among the five domains of VSC issues, the economic domain with a weight of 0.4262 is the most important domain, followed by the management (0.2672), operational (0.2222), environmental (0.0532) and social (0.0312).

Research limitations/implications

This study focuses on the prioritization of VSC issues; therefore, the results of the present study can provide direction to the decision-makers of immunization programs of developing countries in driving their efforts and resources on eliminating the most important obstacles to design successful vaccination programs.

Originality/value

To the authors’ knowledge, this paper is first to provide a direction to the decision-makers in identifying and managing important issues through the use of an analytical approach.

Evaluating the cost per child vaccinated with full versus fractional-dose inactivated poliovirus vaccine

Introduction

Inactivated poliovirus vaccine (IPV) shortages and evidence of improved immunogenicity of two intradermal (ID) fractional IPV (fIPV) doses compared with one full intramuscular dose led to recommendations for fIPV delivery. To provide evidence on the economics of fIPV, we estimated the cost per child vaccinated using full-dose IPV compared with fIPV in routine and campaign settings. We evaluated the impact on costs of alternative devices facilitating ID administration, vaccine vial sizes, and prices.

Methods

We used an Excel-based model to estimate the commodity and delivery costs for providing IPV. Commodity costs included vaccine price per dose adjusted for wastage, prices for vaccine administration devices, and safety boxes. Delivery costs included storage costs at each level of the supply chain, transport costs for commodities between levels, and human resource costs for vaccine administration. Model inputs were obtained from various databases and published literature. All costs are reported in 2018 US dollars.

Results

In both campaign and routine settings, fIPV had a lower cost per child vaccinated than full dosing, despite the assumed higher vaccine wastage with fIPV in routine settings, and even when novel ID administration devices were used. In routine settings, costs per child fully vaccinated with fractional doses were 15% to 48% lower than those with full-dose delivery across different vial sizes. The cost per child vaccinated ranged from $1.84 to $2.65 for fractional doses, depending on the administration device, compared with $3.57 for full dose, when using 5-dose vials. The magnitude of cost reductions with fIPV relative to full-dose IPV was largest with smaller vial sizes and higher vaccine price.

Conclusion

Adopting fIPV can reduce costs per child vaccinated compared with using full doses, especially as IPV prices increase in the short term and more so when two full doses could be recommended in the future.

Enhanced immunity in intradermal vaccination by novel hollow microneedles

BACKGROUND

The intradermal (ID) route for vaccination represents an effective alternative to subcutaneous (SC)/intramuscular administration to induce protective immunity. However, a critical issue associated with ID vaccination is the precise delivery of solution in the upper dermis, which ensures enhanced immunity.

METHODS

We fabricated a hollow microneedle unit made of poly-glycolic acid by injection molding and bonding, and created a dedicated prototype injector. To ensure ID delivery of solution, the injected site was macroscopically and microscopically examined. Serum immunoglobulin G antibody production was measured by enzyme immunoassay and compared in groups of rats following either ID delivery with microneedles or SC administration with a 27-G stainless needle of graded vaccine doses.

RESULTS

The unit used a tandem array of six microneedles, each with a side delivery hole, and a conduit inside for solution. Microneedles installed in the injector punctured the skin with the aid of a spring. Injection of solution formed a wheal due to ID distribution. Histologically, a wedge-shaped skin defect in the upper skin corresponded to each puncture site. Antibody titers following vaccinations on days 1 and 8 were significantly higher with ID injection than with SC delivery on day 15 and every 7 days thereafter until day 36 with mumps vaccination, and until day 36 with varicella vaccination.

CONCLUSIONS

The microneedle unit presented here delivered solution intradermally without any difficulty and evoked antibody responses against viruses even with the reduced vaccine volume. Our findings confirm promising results of ID delivery as an immunogenic option to enhance vaccination efficacy.

Intradermal Administration of Fractional Doses of Inactivated Poliovirus Vaccine: A Dose-Sparing Option for Polio Immunization

A fractional dose of inactivated poliovirus vaccine (fIPV) administered by the intradermal route delivers one fifth of the full vaccine dose administered by the intramuscular route and offers a potential dose-sparing strategy to stretch the limited global IPV supply while further improving population immunity. Multiple studies have assessed immunogenicity of intradermal fIPV compared with the full intramuscular dose and demonstrated encouraging results. Novel intradermal devices, including intradermal adapters and disposable-syringe jet injectors, have also been developed and evaluated as alternatives to traditional Bacillus Calmette-Guérin needles and syringes for the administration of fIPV. Initial experience in India, Pakistan, and Sri Lanka suggests that it is operationally feasible to implement fIPV vaccination on a large scale. Given the available scientific data and operational feasibility shown in early-adopter countries, countries are encouraged to consider introducing a fIPV strategy into their routine immunization and supplementary immunization activities.