Measles vaccination using a microneedle patch

Fourth dose of microneedle array patch of SARS-CoV-2 S1 protein subunit vaccine elicits robust long-lasting humoral responses in mice

The COVID-19 pandemic has underscored the pressing need for safe and effective booster vaccines, particularly in considering the emergence of new SARS-CoV-2 variants and addressing vaccine distribution inequalities. Dissolving microneedle array patches (MAP) offer a promising delivery method, enhancing immunogenicity and improving accessibility through the skin's immune potential. In this study, we evaluated a microneedle array patch-based S1 subunit protein COVID-19 vaccine candidate, which comprised a bivalent formulation targeting the Wuhan and Beta variant alongside a monovalent Delta variant spike proteins in a murine model. Notably, the second boost of homologous bivalent MAP-S1(WU + Beta) induced a 15.7-fold increase in IgG endpoint titer, while the third boost of heterologous MAP-S1RS09Delta yielded a more modest 1.6-fold increase. Importantly, this study demonstrated that the administration of four doses of the MAP vaccine induced robust and long-lasting immune responses, persisting for at least 80 weeks. These immune responses encompassed various IgG isotypes and remained statistically significant for one year. Furthermore, neutralizing antibodies against multiple SARS-CoV-2 variants were generated, with comparable responses observed against the Omicron variant. Overall, these findings emphasize the potential of MAP-based vaccines as a promising strategy to combat the evolving landscape of COVID-19 and to deliver a safe and effective booster vaccine worldwide.

Assessing Reuse of Hypodermic Needles in Mice by means of Digital Imaging, Photomicrography, Bacterial Culture, Analysis of Nest Building, and Animal Vocalization

Hypodermic needles are sometimes reused in animal research settings to preserve the viability of and to conserve limited quantities of injected material. However, the reuse of needles is strongly discouraged in human medicine to prevent inju- ries and the spread of infectious disease. No official guidelines prohibit needle reuse in veterinary medicine, although the practice may be discouraged. We hypothesized that reused needles would be significantly more blunt than unused needles and that reuse for additional injections would cause more animal stress. To test these ideas, we evaluated mice that were injected subcutaneously in the flank or mammary fat pad to generate cell line xenograft and mouse allograft models. Needles were reused up to 20 times, based on an IACUC-approved protocol. A subset of reused needles was digitally imaged to determine needle dullness based on the area of deformation from the secondary bevel angle; this parameter was not different between new needles and needles that had been reused 20 times. In addition, the number of times a needle was reused was not significantly related to audible mouse vocalization during injection. Finally, nest building scores for mice that were injected with a needle used 0 through 5 times were similar to those of mice injected with a needle had been used 16 through 20 times. Among the 37 reused needles that were tested, 4 were positive for bacterial growth; the only organisms cultured were Staphylococcus spp. Contrary to our hypothesis, reusing needles for subcutaneous injections did not increase animal stress based on analysis of vocalization or nest building.

Measles in non-human primates

It is six decades since the measles vaccine was first introduced, and yet we continue to see frequent outbreaks of this disease occurring all over the world. Many non-human primate (NHP) species, including apes, are susceptible to the measles virus. Spontaneous measles outbreaks have been described in a number of zoos and primate centers worldwide. Research into the spontaneous and experimental infection of laboratory primates with measles represents an invaluable source of information regarding the biology and pathogenesis of this virus and continues to be an irreplaceable and unique tool for testing vaccines and treatments. The purpose of this literature review is to summarize and analyze published data on the circulation of the measles virus among free-living synanthropic and captive primate populations, as well as the results of experiments that have modeled this infection in NHPs.

Microarray patches: scratching the surface of vaccine delivery

INTRODUCTION

Microneedles are emerging as a promising technology for vaccine delivery, with numerous advantages over traditional needle and syringe methods. Preclinical studies have demonstrated the effectiveness of MAPs in inducing robust immune responses over traditional needle and syringe methods, with extensive studies using vaccines targeted against different pathogens in various animal models. Critically, the clinical trials have demonstrated safety, immunogenicity, and patient acceptance for MAP-based vaccines against influenza, measles, rubella, and SARS-CoV-2.

AREAS COVERED

This review provides a comprehensive overview of the different types of microarray patches (MAPs) and analyses of their applications in preclinical and clinical vaccine delivery settings. This review also covers additional considerations for microneedle-based vaccination, including adjuvants that are compatible with MAPs, patient safety and factors for global vaccination campaigns.

EXPERT OPINION

MAP vaccine delivery can potentially be a game-changer for vaccine distribution and coverage in both high-income and low- and middle-income countries. For MAPs to reach this full potential, many critical hurdles must be overcome, such as large-scale production, regulatory compliance, and adoption by global health authorities. However, given the considerable strides made in recent years by MAP developers, it may be possible to see the first MAP-based vaccines in use within the next 5 years.

Study protocol for a phase 1/2, single-centre, double-blind, double-dummy, randomized, active-controlled, age de-escalation trial to assess the safety, tolerability and immunogenicity of a measles and rubella vaccine delivered by a microneedle patch in healthy adults (18 to 40 years), measles and rubella vaccine-primed toddlers (15 to 18 months) and measles and rubella vaccine-naïve infants (9 to 10 months) in The Gambia [Measles and Rubella Vaccine Microneedle Patch Phase 1/2 Age De-escalation Trial]

BACKGROUND

New strategies to increase measles and rubella vaccine coverage, particularly in low- and middle-income countries, are needed if elimination goals are to be achieved. With this regard, measles and rubella vaccine microneedle patches (MRV-MNP), in which the vaccine is embedded in dissolving microneedles, offer several potential advantages over subcutaneous delivery. These include ease of administration, increased thermostability, an absence of sharps waste, reduced overall costs and pain-free administration. This trial will provide the first clinical trial data on MRV-MNP use and the first clinical vaccine trial of MNP technology in children and infants.

METHODS

This is a phase 1/2, randomized, active-controlled, double-blind, double-dummy, age de-escalation trial. Based on the defined eligibility criteria for the trial, including screening laboratory investigations, 45 adults [18-40 years] followed by 120 toddlers [15-18 months] and 120 infants [9-10 months] will be enrolled in series. To allow double-blinding, participants will receive either the MRV-MNP and a placebo (0.9% sodium chloride) subcutaneous (SC) injection or a placebo MNP and the MRV by SC injection (MRV-SC). Local and systemic adverse event data will be collected for 14 days following study product administration. Safety laboratories will be repeated on day 7 and, in the adult cohort alone, on day 14. Unsolicited adverse events including serious adverse events will be collected until the final study visit for each participant on day 180. Measles and rubella serum neutralizing antibodies will be measured at baseline, on day 42 and on day 180. Cohort progression will be dependent on review of the unblinded safety data by an independent data monitoring committee.

DISCUSSION

This trial will provide the first clinical data on the use of a MNP to deliver the MRV and the first data on the use of MNPs in a paediatric population. It will guide future product development decisions for what may be a key technology for future measles and rubella elimination.

TRIAL REGISTRATION

Pan-African Clinical Trials Registry 202008836432905 .

CLINICALTRIALS

gov NCT04394689.

An update on biomaterials as microneedle matrixes for biomedical applications

Microneedles (MNs) have been developed for various applications such as drug delivery, cosmetics, diagnosis, and biosensing. To meet the requirements of MNs used in these areas, numerous materials have been used for the fabrication of MNs. However, MNs will be exposed to skin tissues after piercing the stratum corneum barrier. Thus, it is necessary to ensure that the matrix materials of MNs have the characteristics of low toxicity, good biocompatibility, biodegradability, and sufficient mechanical properties for clinical application. In this review, the matrix materials currently used for preparing MNs are summarized and reviewed in terms of these factors. In addition, MN products used on the market and their applications are summarized in the end. This work may provide some basic information to researchers in the selection of MN matrix materials and in developing new materials.

Updates on Measles Incidence and Eradication: Emphasis on the Immunological Aspects of Measles Infection

Measles is an RNA virus infectious disease mainly seen in children. Despite the availability of an effective vaccine against measles, it remains a health issue in children. Although it is a self-limiting disease, it becomes severe in undernourished and immune-compromised individuals. Measles infection is associated with secondary infections by opportunistic bacteria due to the immunosuppressive effects of the measles virus. Recent reports highlight that measles infection erases the already existing immune memory of various pathogens. This review covers the incidence, pathogenesis, measles variants, clinical presentations, secondary infections, elimination of measles virus on a global scale, and especially the immune responses related to measles infection.

Potential of Microneedle Systems for COVID-19 Vaccination: Current Trends and Challenges

To prevent the coronavirus disease 2019 (COVID-19) pandemic and aid restoration to prepandemic normality, global mass vaccination is urgently needed. Inducing herd immunity through mass vaccination has proven to be a highly effective strategy for preventing the spread of many infectious diseases, which protects the most vulnerable population groups that are unable to develop immunity, such as people with immunodeficiencies or weakened immune systems due to underlying medical or debilitating conditions. In achieving global outreach, the maintenance of the vaccine potency, transportation, and needle waste generation become major issues. Moreover, needle phobia and vaccine hesitancy act as hurdles to successful mass vaccination. The use of dissolvable microneedles for COVID-19 vaccination could act as a major paradigm shift in attaining the desired goal to vaccinate billions in the shortest time possible. In addressing these points, we discuss the potential of the use of dissolvable microneedles for COVID-19 vaccination based on the current literature.

Microneedle-Based Vaccine Delivery: Review of an Emerging Technology

Vaccination has produced a great improvement to the global health by decreasing/eradicating many infectious diseases responsible for significant morbidity and mortality. Thanks to vaccines, many infections affecting childhood have been greatly decreased or even eradicated (smallpox, measles, and polio). That is why great efforts are made to achieve mass vaccination against COVID-19. However, developed vaccines face many challenges with regard to their safety and stability. Moreover, needle phobia could prevent a significant proportion of the population from receiving vaccines. In this context, microneedles (MNs) could potentially present a solution to address these challenges. MNs represent single dose administration systems that do not need reconstitution or cold-chain storage. Being self-administered, pain-free, and capable of producing superior immunogenicity makes them a more attractive alternative. This review explores microneedles’ types, safety, and efficacy in vaccine delivery. Preclinical and clinical studies for microneedle-based vaccines are discussed and patent examples are included.

Low-Temperature Multiple Micro-Dispensing on Microneedles for Accurate Transcutaneous Smallpox Vaccination

Smallpox is an acute contagious disease caused by the variola virus. According to WHO guidelines, the smallpox vaccine is administrated by scarification into the epidermis using a bifurcated needle moistened with a vaccine solution. However, this invasive vaccination method involving multiple skin punctures requires a special technique to inoculate, as well as a cold chain for storage and distribution of vaccine solutions containing a live virus. Here, we report a transcutaneous smallpox vaccination using a live vaccinia-coated microneedle (MN) patch prepared by a low-temperature multiple nanoliter-level dispensing system, enabling accurate transdermal delivery of live vaccines and maintenance of bioactivity. The live vaccinia in hyaluronic acid (HA) solutions was selectively coated on the solid MN tips, and the coating amount of the vaccine was precisely controlled through a programmed multiple dispensing process with high accuracy under low temperature conditions (2–8 °C) for smallpox vaccination. Inoculation of mice (BALB/C mouse) with the MN patch coated with the second-generation smallpox vaccine increased the neutralizing antibody titer and T cell immune response. Interestingly, the live vaccine-coated MN patch maintained viral titers at −20 °C for 4 weeks and elevated temperature (37 °C) for 1 week, highlighting improved storage stability of the live virus formulated into coated MN patches. This coated MN platform using contact dispensing technique provides a simple and effective method for smallpox vaccination.

Design and fabrication of r-hirudin loaded dissolving microneedle patch for minimally invasive and long-term treatment of thromboembolic disease

Cardiovascular disease is the leading cause of global mortality, with anticoagulant therapy being the main prevention and treatment strategy. Recombinant hirudin (r-hirudin) is a direct thrombin inhibitor that can potentially prevent thrombosis via subcutaneous (SC) and intravenous (IV) administration, but there is a risk of haemorrhage via SC and IV. Thus, microneedle (MN) provides painless and sanitary alternatives to syringes and oral administration. However, the current technological process for the micro mould is complicated and expensive. The micro mould obtained via three-dimensional (3D) printing is expected to save time and cost, as well as provide a diverse range of MNs. Therefore, we explored a method for MNs array model production based on 3D printing and translate it to micro mould that can be used for fabrication of dissolving MNs patch. The results show that r-hirudin-loaded and hyaluronic acid (HA)-based MNs can achieve transdermal drug delivery and exhibit significant potential in the prevention of thromboembolic disease without bleeding in animal models. These results indicate that based on 3D printing technology, MNs combined with r-hirudin are expected to achieve diverse customizable MNs and thus realize personalized transdermal anticoagulant delivery for minimally invasive and long-term treatment of thrombotic disease.

Microneedle patch as a new platform to effectively deliver inactivated polio vaccine and inactivated rotavirus vaccine

We recently reported a lack of interference between inactivated rotavirus vaccine (IRV) and inactivated poliovirus vaccine (IPV) and their potential dose sparing when the two vaccines were administered intramuscularly either in combination or standalone in rats and guinea pigs. In the present study, we optimized the formulations of both vaccines and investigated the feasibility of manufacturing a combined IRV-IPV dissolving microneedle patch (dMNP), assessing its compatibility and immunogenicity in rats. Our results showed that IRV delivered by dMNP alone or in combination with IPV induced similar levels of RV-specific IgG and neutralizing antibody. Likewise, IPV delivered by dMNP alone or in combination with IRV induced comparable levels of neutralizing antibody of poliovirus types 1, 2, and 3. We further demonstrated high stability of IRV-dMNP at 5, 25, and 40 °C and IPV-dMNP at 5 and 25 °C, and found that three doses of IRV or IPV when co-administered at a quarter dose was as potent as a full target dose in inducing neutralizing antibodies against corresponding rotavirus or poliovirus. We conclude that IRV-IPV dMNP did not interfere with each other in triggering an immunologic response and were highly immunogenic in rats. Our findings support the further development of this innovative approach to deliver a novel combination vaccine against rotavirus and poliovirus in children throughout the world.

Non-dermal applications of microneedle drug delivery systems

Microneedles (MNs) are micron-scaled needles measuring 100 to 1000 μm that were initially explored for delivery of therapeutic agents across the skin. Considering the success in transcutaneous drug delivery, the application of microneedles has been extended to different tissues and organs. The review captures the application of microneedles to the oral mucosa, the eye, vagina, gastric mucosa, nail, scalp, and vascular tissues for delivery of vaccines, biologics, drugs, and diagnostic agents. The technology has created easy access to the poorly accessible segments of eye to facilitate delivery of monoclonal antibodies and therapeutic agents in management of neovascular disease. Microporation has been reported to drastically improve the drug delivery through the poorly permeable nail plate. Curved microneedles and spatially designed microneedle cuffs have been found to be capable of delivering stem cells and therapeutic macromolecules directly to the cardiac tissue and the vascular smooth muscle cells, respectively. Besides being minimally invasive and patient compliant, the technology has the potential to offer viable solutions to deliver drugs through impermeable barriers owing to the ability to penetrate several biological barriers. The technology has been successful to overcome the delivery hurdles and enable direct delivery of drug to the target sites, thus maximizing the efficacy thereby reducing the required dose. This review is an attempt to capture the non-dermatological applications of microneedles being explored and provides an insight on the future trends in the field of microneedle technology. Pictorial representation of different microneedle application.

Thermostability of Measles and Rubella Vaccines in a Microneedle Patch

Measles and rubella vaccinations are highly effective at reducing disease prevalence; however, logistic issues related to subcutaneous administration and vaccine wastage limit the extent of vaccination coverage. Microneedle (MN) patches can increase coverage by easing logistics through simplified administration and improved stability. This study demonstrates the thermostability of a bivalent measles and rubella vaccine MN patch. Rubella vaccine stability required pH buffering during drying; potassium phosphate buffer at neutral pH was optimal for both vaccines. Screening 43 excipients for their ability to retain potency during drying and storage yielded sucrose-threonine-potassium phosphate buffer formulation at pH 7.5 as an optimal formulation. MN patches made with this formulation had no significant loss of vaccine titer after one month and remained within a one log₁₀ titer loss cutoff after 3 - 4 months at 5°C, 25°C and 40°C. Finally, these patches were shown to be immunogenic in juvenile rhesus macaques. This work demonstrates the potential for MN patches for measles and rubella vaccination to be removed from the cold chain, which is expected to decrease vaccine cost and wastage, and increase vaccination coverage.

Microneedle-Mediated Vaccination: Innovation and Translation

Vaccine administration by subcutaneous or intramuscular injection is the most commonly prescribed route for inoculation, however, it is often associated with some deficiencies such as low compliance, high professionalism, and risk of infection. Therefore, the application of microneedles for vaccine delivery has gained widespread interests in the past few years due to its high compliance, minimal invasiveness, and convenience. This review focuses on recent advances in the development and application of microneedles for vaccination based on different delivery strategies, and introduces the current status of microneedle-mediated vaccination in clinical translation. The prospects for its application including opportunities and challenges are further discussed.

Manufacturing Process of Polymeric Microneedle Sensors for Mass Production

In this work, we present a fabrication process for microneedle sensors made of polylactic acid (PLA), which can be utilized for the electrochemical detection of various biomarkers in interstitial fluid. Microneedles were fabricated by the thermal compression molding of PLA into a laser machined polytetrafluoroethylene (PTFE) mold. Sensor fabrication was completed by forming working, counter, and reference electrodes on each sensor surface by Au sputtering through a stencil mask, followed by laser dicing to separate individual sensors from the substrate. The devised series of processes was designed to be suitable for mass production, where multiple microneedle sensors can be produced at once on a 4-inch wafer. The operational stability of the fabricated sensors was confirmed by linear sweep voltammetry and cyclic voltammetry at the range of working potentials of various biochemical molecules in interstitial fluid.

Microneedle arrays integrated with living organisms for smart biomedical applications

Various living organisms have proven to influence human health significantly, either in a commensal or pathogenic manner. Harnessing the creatures may remarkably improve human healthcare and cure the intractable illness that is challenged using traditional drugs or surgical approaches. However, issues including limited biocompatibility, poor biosafety, inconvenience for personal handling, and low patient compliance greatly hinder the biomedical and clinical applications of living organisms when adopting them for disease treatment. Microneedle arrays (MNAs), emerging as a promising candidate of biomedical devices with the functional diversity and minimal invasion, have exhibited great potential in the treatment of a broad spectrum of diseases, which is expected to improve organism-based therapies. In this review, we systemically summarize the technologies employed for the integration of MNAs with specific living organisms including diverse viruses, bacteria, mammal cells and so on. Moreover, their applications such as vaccination, anti-infection, tumor therapy and tissue repairing are well illustrated. Challenges faced by current strategies, and the perspectives of integrating more living organisms, adopting smarter materials, and developing more advanced technologies in MNAs for future personalized and point-of-care medicine, are also discussed. It is believed that the combination of living organisms with functional MNAs would hold great promise in the near future due to the advantages of both biological and artificial species.

Formulation Development and Improved Stability of a Combination Measles and Rubella Live-Viral Vaccine Dried for Use in the NanopatchTM Microneedle Delivery System

Measles (Me) and rubella (Ru) viral diseases are targeted for elimination by ensuring a high level of vaccination coverage worldwide. Less costly, more convenient MeRu vaccine delivery systems should improve global vaccine coverage, especially in low - and middle - income countries (LMICs). In this work, we examine formulating a live, attenuated Me and Ru combination viral vaccine with Nanopatch™, a solid polymer micro-projection array for intradermal delivery. First, high throughput, qPCR-based viral infectivity and genome assays were established to enable formulation development to stabilize Me and Ru in a scaled-down, custom-built evaporative drying system to mimic the Nanopatch™ vaccine coating process. Second, excipient screening and optimization studies identified virus stabilizers for use during the drying process and upon storage in the dried state. Finally, a series of real-time and accelerated stability studies identified eight candidate formulations that met a target thermal stability criterion for live vaccines (<1 log10 loss after 1 week storage at 37°C). Compared to -80°C control samples, the top candidate formulations resulted in minimal viral infectivity titer losses after storage at 2-8°C for 6 months (i.e., <0.1 log10 for Me, and ~0.4 log10 for Ru). After storage at 25°C over 6 months, ~0.3-0.5 and ~1.0-1.4 log10 titer losses were observed for Me and Ru, respectively, enabling the rank-ordering of the stability of candidate formulations. These results are discussed in the context of future formulation challenges for developing microneedle-based dosage forms containing stabilized live, attenuated viral vaccines for use in LMICs.

Transdermal drug delivery systems for fighting common viral infectious diseases

Transdermal drug delivery systems (TDDS) have many advantages and represent an excellent alternative to oral delivery and hypodermic injections. TDDS are more convenient and less invasive tools for disease and viral infection treatment, prevention, detection, and surveillance. The emerging development of microneedles for TDDS has facilitated improved skin barrier penetration for the delivery of macromolecules or hydrophilic drugs. Microneedle TDDS patches can be fabricated to deliver virus vaccines and potentially provide a viable alternative vaccine modality that offers improved immunogenicity, thermostability, simplicity, safety, and compliance as well as sharp-waste reduction, increased cost-effectiveness, and the capacity for self-administration, which could improve vaccine distribution. These advantages make TDDS-based vaccine delivery an especially well-suited option for treatment of widespread viral infectious diseases including pandemics. Because microneedle-based bioassays employ transdermal extraction of interstitial fluid or blood, they can be used as a minimally invasive approach for surveying disease markers and providing point-of-care (POC) diagnostics. For cutaneous viral infections, TDDS can provide localized treatment with high specificity and less systemic toxicity. In summary, TDDS, especially those that employ microneedles, possess special attributes that can be leveraged to reduce morbidity and mortality from viral infectious diseases. In this regard, they may have considerable positive impact as a modality for improving global health. In this article, we introduce the possible role and summarize the current literature regarding TDDS applications for fighting common cutaneous or systemic viral infectious diseases, including herpes simplex, varicella or herpes zoster, warts, influenza, measles, and COVID-19.

Microarray patches enable the development of skin-targeted vaccines against COVID-19

The COVID-19 pandemic is a serious threat to global health and the global economy. The ongoing race to develop a safe and efficacious vaccine to prevent infection by SARS-CoV-2, the causative agent for COVID-19, highlights the importance of vaccination to combat infectious pathogens. The highly accessible cutaneous microenvironment is an ideal target for vaccination since the skin harbors a high density of antigen-presenting cells and immune accessory cells with broad innate immune functions. Microarray patches (MAPs) are an attractive intracutaneous biocargo delivery system that enables safe, reproducible, and controlled administration of vaccine components (antigens, with or without adjuvants) to defined skin microenvironments. This review describes the structure of the SARS-CoV-2 virus and relevant antigenic targets for vaccination, summarizes key concepts of skin immunobiology in the context of prophylactic immunization, and presents an overview of MAP-mediated cutaneous vaccine delivery. Concluding remarks on MAP-based skin immunization are provided to contribute to the rational development of safe and effective MAP-delivered vaccines against emerging infectious diseases, including COVID-19.

Emerging skin-targeted drug delivery strategies to engineer immunity: A focus on infectious diseases

INTRODUCTION

Infectious pathogens are global disrupters. Progress in biomedical science and technology has expanded the public health arsenal against infectious diseases. Specifically, vaccination has reduced the burden of infectious pathogens. Engineering systemic immunity by harnessing the cutaneous immune network has been particularly attractive since the skin is an easily accessible immune-responsive organ. Recent advances in skin-targeted drug delivery strategies have enabled safe, patient-friendly, and controlled deployment of vaccines to cutaneous microenvironments for inducing long-lived pathogen-specific immunity to mitigate infectious diseases, including COVID-19.

AREAS COVERED

This review briefly discusses the basics of cutaneous immunomodulation and provides a concise overview of emerging skin-targeted drug delivery systems that enable safe, minimally invasive, and effective intracutaneous administration of vaccines for engineering systemic immune responses to combat infectious diseases.

EXPERT OPINION

In-situ engineering of the cutaneous microenvironment using emerging skin-targeted vaccine delivery systems offers remarkable potential to develop diverse immunization strategies against pathogens. Mechanistic studies with standard correlates of vaccine efficacy will be important to compare innovative intracutaneous drug delivery strategies to each other and to existing clinical approaches. Cost-benefit analyses will be necessary for developing effective commercialization strategies. Significant involvement of industry and/or government will be imperative for successfully bringing novel skin-targeted vaccine delivery methods to market for their widespread use.

Progress in microneedle array patch (MAP) for vaccine delivery

A microneedle array patch (MAP) has been developed as a new delivery system for vaccines. Preclinical and clinical trials with a vaccine MAP showed improved stability, safety, and immunological efficacy compared to conventional vaccine administration. Various vaccines can be delivered with a MAP. Currently, microneedle manufacturers can mass-produce pharmaceutical MAP and cosmetic MAP and this mass-production system can be adapted to produce a vaccine MAP. Clinical trials with a vaccine MAP have shown comparable efficacy with conventional administration, and discussions about regulations for a vaccine MAP are underway. However, there are concerns of reasonable cost, mass production, efficacy, and safety standards that meet FDA approval, as well as the need for feedback regarding the best method of administration. Currently, microneedles have been studied for the delivery of many kinds of vaccines, and preclinical and clinical studies of vaccine microneedles are in progress. For the foreseeable future, some vaccines will continue to be administered with syringes and needles while the use of a vaccine MAP continues to be improved because of the advantages of less pain, self-administration, improved stability, convenience, and safety.

Measles and rubella microarray array patches to increase vaccination coverage and achieve measles and rubella elimination in Africa

The African Region is committed to measles elimination by 2020 but coverage with the first dose of measles-containing vaccine was only 70% in 2017. Several obstacles to achieving high coverage with measles and rubella vaccines exist, some of which could be overcome with new vaccine delivery technologies. Microarray array patches (MAPs) are single-dose devices used for transcutaneous administration of molecules, including inactivated or attenuated vaccines, that penetrate the outer stratum corneum of the skin, delivering antigens to the epidermis or dermis. MAPs to deliver measles and rubella vaccines have the potential to be a transformative technology to achieve elimination goals in the African Region. MAPs for measles and rubella vaccination have been shown to be safe, immunogenic and thermostable in preclinical studies but results of clinical studies in humans have not yet been published. This review summarizes the current state of knowledge of measles and rubella MAPs, their potential advantages for immunization programs in the African Region, and some of the challenges that must be overcome before measles and rubella MAPs are available for widespread use.

Materials for Immunotherapy

Breakthroughs in materials engineering have accelerated the progress of immunotherapy in preclinical studies. The interplay of chemistry and materials has resulted in improved loading, targeting, and release of immunomodulatory agents. An overview of the materials that are used to enable or improve the success of immunotherapies in preclinical studies is presented, from immunosuppressive to proinflammatory strategies, with particular emphasis on technologies poised for clinical translation. The materials are organized based on their characteristic length scale, whereby the enabling feature of each technology is organized by the structure of that material. For example, the mechanisms by which i) nanoscale materials can improve targeting and infiltration of immunomodulatory payloads into tissues and cells, ii) microscale materials can facilitate cell-mediated transport and serve as artificial antigen-presenting cells, and iii) macroscale materials can form the basis of artificial microenvironments to promote cell infiltration and reprogramming are discussed. As a step toward establishing a set of design rules for future immunotherapies, materials that intrinsically activate or suppress the immune system are reviewed. Finally, a brief outlook on the trajectory of these systems and how they may be improved to address unsolved challenges in cancer, infectious diseases, and autoimmunity is presented.

A microneedle patch for measles and rubella vaccination: a game changer for achieving elimination

While morbidity and mortality associated with measles and rubella (MR) have dramatically decreased, there are still >100000 estimated deaths due to measles and an estimated 100000 infants born with congenital rubella syndrome annually. Given highly effective MR vaccines, the primary barrier to global elimination of these diseases is low vaccination coverage, especially among the most underserved populations in resource-limited settings. In contrast to conventional MR vaccination by hypodermic injection, microneedle patches are being developed to enable MR vaccination by minimally trained personnel. Simplified supply chain, reduced need for cold chain storage, elimination of vaccine reconstitution, no sharps waste, reduced vaccine wastage, and reduced total system cost of vaccination are advantages of this approach. Preclinical work to develop a MR vaccine patch has proceeded through successful immunization studies in rodents and non-human primates. On-going programs seek to make MR vaccine patches available to support MR elimination efforts around the world.

The potential role of using vaccine patches to induce immunity: platform and pathways to innovation and commercialization

Introduction: In the last two decades, the evidence related to using vaccine patches with multiple short projections (≤1 mm) to deliver vaccines through the skin increased significantly and demonstrated their potential as an innovative delivery platform.Areas covered: We review the vaccine patch literature published in English as of 1 March 2019, as well as available information from key stakeholders related to vaccine patches as a platform. We identify key research topics related to basic and translational science on skin physical properties and immunobiology, patch development, and vaccine manufacturing.Expert opinion: Currently, vaccine patch developers continue to address some basic science and other platform issues in the context of developing a potential vaccine patch presentation for an existing or new vaccine. Additional clinical data and manufacturing experience could shift the balance toward incentivizing existing vaccine manufactures to further explore the use of vaccine patches to deliver their products. Incentives for innovation of vaccine patches differ for developed and developing countries, which will necessitate different strategies (e.g. public-private partnerships, push, or pull mechanisms) to support the basic and applied research needed to ensure a strong evidence base and to overcome translational barriers for vaccine patches as a delivery platform.

Understanding the basis of transcutaneous vaccine delivery

Under many circumstances, prophylactic immunizations are considered as the only possible strategy to control infectious diseases. Considerable efforts are typically invested in immunogen selection but, erroneously, the route of administration is not usually a major concern despite the fact that it can strongly influence efficacy. The skin is now considered a key component of the lymphatic system with tremendous potential as a target for vaccination. The purpose of this review is to present the immunological basis of the skin-associated lymphoid tissue, so as to provide understanding of the skin vaccination strategies. Several strategies are currently being developed for the transcutaneous delivery of antigens. The classical, mechanical or chemical disruptions versus the newest approaches based on microneedles for antigen delivery through the skin are discussed herein.

Immune response and reactogenicity of an unadjuvanted intradermally delivered human papillomavirus vaccine using a first generation Nanopatch™ in rhesus macaques: An exploratory, pre-clinical feasibility assessment

The human papillomavirus (HPV) 9-valent, recombinant vaccine (Gardasil™9) helps protect young adults (males and females) against anogenital cancers and genital warts caused by certain HPV genotypes (ref. Gardasil™9 insert). This vaccine is administered intramuscularly (IM). The aim of this study was to determine preclinically whether intradermal (ID) vaccination with an unadjuvanted 9-valent recombinant HPV vaccine using a first-generation ID delivery device, the Nanopatch™, could enhance vaccine immunogenicity compared with the traditional ID route (Mantoux technique). IM injection of HPV VLPs formulated with Merck & Co., Inc., Kenilworth, NJ, USA Alum Adjuvant (MAA) were included in the rhesus study for comparison. The Nanopatch™ prototype contains a high-density array comprised of 10,000 microprojections/cm², each 250 µm long. It was hypothesized the higher density array with shallower ID delivery may be superior to the Mantoux technique. To test this hypothesis, HPV VLPs without adjuvant were coated on the Nanopatch™, stability of the Nanopatch™ with unadjuvanted HPV VLPs were evaluated under accelerated conditions, skin delivery was verified using radiolabelled VLPs or FluoSpheres®, and the immune response and skin site reaction with the Nanopatch™ was evaluated in rhesus macaques. The immune response induced by Nanopatch™ administration, measured as HPV-specific binding antibodies, was similar to that induced using the Mantoux technique. It was also observed that a lower dose of unadjuvanted HPV VLPs delivered with the first-generation Nanopatch™ and applicator or Mantoux technique resulted in an immune response that was significantly lower compared to a higher-dose of alum adjuvanted HPV VLPs delivered IM in rhesus macaques. The study also indicated unadjuvanted HPV VLPs could be delivered with the first-generation Nanopatch™ and applicator to the skin in 15 s with a transfer efficiency of approximately 20%. This study is the first demonstration of patch administration in non-human primates with a vaccine composed of HPV VLPs.

Microneedle Coating Methods: A Review with a Perspective

A coated microneedle array comprises sharp micrometer-sized needle shafts attached to a base substrate and coated with a drug on their surfaces. Coated microneedles are under investigation for drug delivery into the skin and other tissues, and a broad assortment of active materials, including small molecules, peptides, proteins, deoxyribonucleic acids, and viruses, have been coated onto microneedles. To coat the microneedles, different methods have been developed. Some coating methods achieve selective coating of just the microneedle shafts, whereas other methods coat not only microneedle shafts but also the array base substrate. Selective coating of just the microneedle shafts is more desirable since it provides control over drug dosage, prevents drug waste, and offers high delivery efficiency. Different excipients are added to the coating liquid to modulate its viscosity and surface tension in order to achieve uniform coatings on microneedles. Coated microneedles have been used in a broad range of biomedical applications. To highlight these different applications, a table summarizing the different active materials and the amounts coated on microneedles is provided. We also discuss factors that should be considered when deciding suitability of coated microneedles for new-drug delivery applications. In recent years, many coated microneedles have been investigated in human clinical trials, and there is now a strong effort to bring the first coated microneedle-based product to market.

Extended delivery of vaccines to the skin improves immune responses

Vaccines prevent 2-3 million childhood deaths annually; however, low vaccine efficacy and the resulting need for booster doses create gaps in immunization coverage. In this translational study, we explore the benefits of extended release of licensed vaccine antigens into skin to increase immune responses after a single dose in order to design improved vaccine delivery systems. By administering daily intradermal injections of inactivated polio vaccine according to six different delivery profiles, zeroth-order release over 28 days resulted in neutralizing antibody titers equivalent to two bolus vaccinations administered one month apart. Vaccinations following this profile also improved immune responses to tetanus toxoid and subunit influenza vaccine but not a live-attenuated viral vaccine, measles vaccine. Finally, using subunit influenza vaccine, we demonstrated that daily vaccination by microneedle patch induced a potent, balanced humoral immunity with an increased memory response compared to bolus vaccination. We conclude that extended presentation of antigen in skin via intradermal injection or microneedle patch can enhance immune responses and reduce the number of vaccine doses, thereby enabling increased vaccination efficacy.

Microneedle-based intradermal delivery of stabilized dengue virus

Current live-attenuated dengue vaccines require strict cold chain storage. Methods to preserve dengue virus (DENV) viability, which enable vaccines to be transported and administered at ambient temperatures, will be decisive towards the implementation of affordable global vaccination schemes with broad immunization coverage in resource-limited areas. We have developed a microneedle (MN)-based vaccine platform for the stabilization and intradermal delivery of live DENV from minimally invasive skin patches. Dengue virus-stabilized microneedle arrays (VSMN) were fabricated using saccharide-based formulation of virus and could be stored dry at ambient temperature up to 3 weeks with maintained virus viability. Following intradermal vaccination, VSMN-delivered DENV was shown to elicit strong neutralizing antibody responses and protection from viral challenge, comparable to that of the conventional liquid vaccine administered subcutaneously. This work supports the potential for MN-based dengue vaccine technology and the progression towards cold chain-independence. Dengue virus can be stabilized using saccharide-based formulations and coated on microneedle array vaccine patches for storage in dry state with preserved viability at ambient temperature (VSMN; virus-stabilized microneedle arrays).

End-user acceptability study of the nanopatch™; a microarray patch (MAP) for child immunization in low and middle-income countries

A promising new delivery technology, the microarray patch (MAPs) consists of an array of small solid-coated or dissolvable needles, up to one mm in length, that administers a dry formulation of a vaccine or pharmaceutical. This study is not a real-life evaluation study but determines the anticipated acceptability of the Nanopatch™, a solid microarray patch device, in Benin, Nepal and Vietnam for vaccine delivery, and identifies factors that could improve the acceptability of the technology to increase measles immunization coverage. This study combined several evaluation methods, including simulation of vaccine administration on children and in-depth interviews with key stakeholders, healthcare workers, community health volunteers, caretakers, and community representatives. A total of 314 people participated in the study. The overall rate of total acceptability of the patch for child immunization was 92.7%. General opinions were very positive, providing clinical studies confirm that MAP administration is demonstrated to be painless, safe and effective for infectious disease prevention. The study participants were asked to consider the best strategy to introduce such vaccine delivery innovation. Firstly, delivery by skilled healthcare workers at the healthcare facilities will be preferred to establish the technology. Following this, administration by selected volunteers and outreach delivery may be possible, though under the supervision of skilled healthcare workers. This study's protocol received approval from the World Health Organization (WHO) Ethical Research Committee (ERC0002813) and the national IRB in Benin, Nepal and Vietnam.

Successes and challenges for preventing measles, mumps and rubella by vaccination

The measles, mumps and rubella (MMR) vaccine has an outstanding safety record and is highly efficacious. High coverage with MMR has led to the elimination of endemic measles, rubella, and congenital rubella syndrome in the US. The biggest challenges to global measles and rubella control and elimination are insufficient vaccination coverage globally and increasing hesitancy. Despite high two dose coverage rates, mumps has made a resurgence in the US and other countries. Mumps outbreaks have occurred primarily in close contact, high-density settings and most cases had received a second dose 10 or more years previously. Waning humoral immunity and antigenic variation of circulating wild-type mumps strains may play a role in the mumps resurgence.

Microneedle-Mediated Vaccine Delivery to the Oral Mucosa

The oral mucosa is a minimally invasive and immunologically rich site that is underutilized for vaccination due to physiological and immunological barriers. To develop effective oral mucosal vaccines, key questions regarding vaccine residence time, uptake, adjuvant formulation, dose, and delivery location must be answered. However, currently available dosage forms are insufficient to address all these questions. An ideal oral mucosal vaccine delivery system would improve both residence time and epithelial permeation while enabling efficient delivery of physicochemically diverse vaccine formulations. Microneedles have demonstrated these capabilities for dermal vaccine delivery. Additionally, microneedles enable precise control over delivery properties like depth, uniformity, and dosing, making them an ideal tool to study oral mucosal vaccination. Select studies have demonstrated the feasibility of microneedle-mediated oral mucosal vaccination, but they have only begun to explore the broad functionality of microneedles. This review describes the physiological and immunological challenges related to oral mucosal vaccine delivery and provides specific examples of how microneedles can be used to address these challenges. It summarizes and compares the few existing oral mucosal microneedle vaccine studies and offers a perspective for the future of the field.

Stability of Vaccines

Vaccines are considered the most economical and effective preventive measure against most deadly infectious diseases. Vaccines help protect around three million lives every year, but hundreds of thousands of lives are lost due to the instability of vaccines. This review discusses the various types of instability observed, while manufacturing, storing, and distributing vaccines. It describes the specific stability problems associated with each type of vaccine. This review also discusses the various measures adopted to overcome these instability problems. Vaccines are classified based on their components, and this review discusses how these preventive measures relate to each type of vaccine. This review also includes certain case studies that illustrate various approaches to improve vaccine stability. Last, this review provides insight on prospective methods for developing more stable vaccines.

The potential effects of introducing microneedle patch vaccines into routine vaccine supply chains

BACKGROUND

Microneedle patch (MNP) technology is designed to simplify the process of vaccine administration; however, depending on its characteristics, MNP technology may provide additional benefits beyond the point-of-use, particularly for vaccine supply chains.

METHODS

Using the HERMES modeling software, we examined replacing four routine vaccines - Measles-containing vaccine (MCV), Tetanus toxoid (TT), Rotavirus (Rota) and Pentavalent (Penta) - with MNP versions in the routine vaccine supply chains of Benin, Bihar (India), and Mozambique.

RESULTS

Replacing MCV with an MNP (5 cm³-per-dose, 2-month thermostability, current single-dose price-per-dose) improved MCV availability by 13%, 1% and 6% in Benin, Bihar and Mozambique, respectively, and total vaccine availability by 1% in Benin and Mozambique, while increasing the total cost per dose administered by $0.07 in Benin, $0.56 in Bihar and $0.11 in Mozambique. Replacing TT with an MNP improved TT and total vaccine availability (3% and <1%) in Mozambique only, when the patch was 5 cm³ and 2-months thermostable but increased total cost per dose administered by $0.14. Replacing Rota with an MNP (at 5-15 cm³-per-dose, 1-2 month thermostable) improved Rota and total vaccine availability, but only improved Rota vaccine availability in Bihar (at 5 cm³, 1-2 months thermostable), while decreasing total vaccine availability by 1%. Finally, replacing Penta with an MNP (at 5 cm³, 2-months thermostable) improved Penta vaccine availability by 1-8% and total availability by <1-9%.

CONCLUSIONS

An MNP for MCV, TT, Rota, or Penta would need to have a smaller or equal volume-per-dose than existing vaccine formulations and be able to be stored outside the cold chain for a continuous period of at least two months to provide additional benefits to all three supply chains under modeled conditions.

Combined effects of osmotic and hydrostatic pressure on multilamellar lipid membranes in the presence of PEG and trehalose

We studied the interaction of lipid membranes with the disaccharide trehalose (TRH), which is known to stabilize biomembranes against various environmental stress factors. Generally, stress factors include low/high temperature, shear, osmotic and hydrostatic pressure. Small-angle X-ray-scattering was applied in combination with fluorescence spectroscopy and calorimetric measurements to get insights into the influence of trehalose on the supramolecular structure, hydration level, and elastic and thermodynamic properties as well as phase behavior of the model biomembrane DMPC, covering a large region of the temperature, osmotic and hydrostatic pressure phase space. We observed distinct effects of trehalose on the topology of the lipid's supramolecular structure. Trehalose, unlike osmotic pressure induced by polyethylene glycol, leads to a decrease of lamellar order and a swelling of multilamellar vesicles, which is attributable to direct interactions between the membrane and trehalose. Our results revealed a distinct biphasic concentration dependence of the observed effects of trehalose. While trehalose intercalates between the polar head groups at low concentrations, the effects after saturation are dominated by the exclusion of trehalose from the membrane surface.

Therapeutic applications and pharmacoeconomics of microneedle technology

INTRODUCTION

Microneedle (MN) arrays contain a backing plate with multiple microscopic projections to puncture the skin and can be used to deliver drug in a minimally invasive way. Advantages of MNs are numerous including administration of large molecules, avoiding first-pass metabolism, ease of administration, lack of pain, site-specific drug targeting, and dose reduction due to increased absorption efficacy. The growth in the transdermal market has been fueled by an increasing number of chronic disease patients and a demand for easy and pain-free drug administration.

AREAS COVERED

This paper highlights the use of MNs as a drug delivery system and discusses their potential market impact from a cost perspective. A number of clinical trials have been conducted and are listed to illustrate the potential applications of MNs for therapeutic use. Furthermore, the cosmetic market has made use of the MN technology, indicating that MNs can be used safely, efficaciously, and on a commercial scale. Furthermore, the cost-effectiveness of MNs is discussed.

EXPERT COMMENTARY

For MNs to become commercially available for therapeutic use, a number of factors will need to be considered: safety, ease of use, manufacturing and storage, uptake, effectiveness, and regulatory requirements.

A Microneedle Patch for Measles and Rubella Vaccination Is Immunogenic and Protective in Infant Rhesus Macaques

Background

New methods to increase measles and rubella (MR) vaccination coverage are needed to achieve global and regional MR elimination goals.

Methods

Here, we developed microneedle (MN) patches designed to administer MR vaccine by minimally trained personnel, leave no biohazardous sharps waste, remove the need for vaccine reconstitution, and provide thermostability outside the cold chain. This study evaluated the immunogenicity of MN patches delivering MR vaccine to infant rhesus macaques.

Results

Protective titers of measles neutralizing antibodies (>120 mIU/mL) were detected in 100% of macaques in the MN group and 75% of macaques in the subcutaneous (SC) injection group. Rubella neutralizing antibody titers were >10 IU/mL for all groups. All macaques in the MN group were protected from challenge with wild-type measles virus, whereas 75% were protected in the SC group. However, vaccination by the MN or SC route was unable to generate protective immune responses to measles in infant macaques pretreated with measles immunoglobulin to simulate maternal antibody.

Conclusions

These results show, for the first time, that MR vaccine delivered by MN patch generated protective titers of neutralizing antibodies to both measles and rubella in infant rhesus macaques and afforded complete protection from measles virus challenge.

Rotavirus Vaccines: Effectiveness, Safety, and Future Directions

Rotavirus is the leading cause of diarrheal death among children < 5 years old worldwide, estimated to have caused ~ 215,000 deaths in 2013. Prior to rotavirus vaccine implementation, > 65% of children had at least one rotavirus diarrhea illness by 5 years of age and rotavirus accounted for > 40% of all-cause diarrhea hospitalizations globally. Two live, oral rotavirus vaccines have been implemented nationally in > 100 countries since 2006 and their use has substantially reduced the burden of severe diarrheal illness in all settings. Vaccine efficacy and effectiveness estimates suggest there is a gradient in vaccine performance between low child-mortality countries (> 90%) and medium and high child-mortality countries (57-75%). Additionally, an increased risk of intussusception (~ 1-6 per 100,000 vaccinated infants) following vaccination has been documented in some countries, but this is outweighed by the large benefits of vaccination. Two additional live, oral rotavirus vaccines were recently licensed and these have improved on some programmatic limitations of earlier vaccines, such as heat stability, cost, and cold-chain footprint. Non-replicating rotavirus vaccines that are parenterally administered are in clinical testing, and these have the potential to reduce the performance differential and safety concerns associated with live oral rotavirus vaccines.

Noninvasive vaccination against infectious diseases

The development of a successful vaccine, which should elicit a combination of humoral and cellular responses to control or prevent infections, is the first step in protecting against infectious diseases. A vaccine may protect against bacterial, fungal, parasitic, or viral infections in animal models, but to be effective in humans there are some issues that should be considered, such as the adjuvant, the route of vaccination, and the antigen-carrier system. While almost all licensed vaccines are injected such that inoculation is by far the most commonly used method, injection has several potential disadvantages, including pain, cross contamination, needlestick injury, under- or overdosing, and increased cost. It is also problematic for patients from rural areas of developing countries, who must travel to a hospital for vaccine administration. Noninvasive immunizations, including oral, intranasal, and transcutaneous administration of vaccines, can reduce or eliminate pain, reduce the cost of vaccinations, and increase their safety. Several preclinical and clinical studies as well as experience with licensed vaccines have demonstrated that noninvasive vaccine immunization activates cellular and humoral immunity, which protect against pathogen infections. Here we review the development of noninvasive immunization with vaccines based on live attenuated virus, recombinant adenovirus, inactivated virus, viral subunits, virus-like particles, DNA, RNA, and antigen expression in rice in preclinical and clinical studies. We predict that noninvasive vaccine administration will be more widely applied in the clinic in the near future.

Microneedles for vaccine delivery: challenges and future perspectives

Vaccine delivery to the skin using conventional needles is associated with needle-stick injuries and needle-phobia, which are all major obstacles to vaccination. The development of microneedles has enabled to overcome these limitations and as a result viral, DNA and bacterial vaccines have been studied for the delivery into the skin. Research has shown the superiority of microneedle vaccination over conventional needles in terms of immunogenicity, vaccine stability and dose-sparing abilities in animals and humans. Additional research on improving vaccine stability and delivering vaccines to other areas of the body besides the skin is ongoing as well. Thus, this review paper describes current advances in microneedles as a delivery system for vaccines as well as future perspectives for this research field.

Transdermal immunomodulation: Principles, advances and perspectives

Immunomodulation, manipulation of the immune responses towards an antigen, is a promising strategy to treat cancer, infectious diseases, allergies, and autoimmune diseases, among others. Unique features of the skin including the presence of tissue-resident immune cells, ease of access and connectivity to other organs makes it a unique target organ for immunomodulation. In this review, we summarize advances in transdermal delivery of agents for modulating the immune responses for vaccination as well as tolerization. The biological foundation of skin-based immunomodulation and challenges in its implementation are described. Technological approaches aimed at enhancing the delivery of immunomodulatory therapeutics into skin are also discussed in this review. Progress made in the treatment of several specific diseases including cancer, infections and allergy are discussed. Finally, this review discusses some practical considerations and offers some recommendations for future studies in the field of transdermal immunomodulation.

Development of Stabilizing Formulations of a Trivalent Inactivated Poliovirus Vaccine in a Dried State for Delivery in the Nanopatch™ Microprojection Array

The worldwide switch to inactivated polio vaccines (IPVs) is a key component of the overall strategy to achieve and maintain global polio eradication. To this end, new IPV vaccine delivery systems may enhance patient convenience and compliance. In this work, we examine Nanopatch™ (a solid, polymer microprojection array) which offers potential advantages over standard needle/syringe administration including intradermal delivery and reduced antigen doses. Using trivalent IPV (tIPV) and a purpose-built evaporative dry-down system, candidate tIPV formulations were developed to stabilize tIPV during the drying process and on storage. Identifying conditions to minimize tIPV potency losses during rehydration and potency testing was a critical first step. Various classes and types of pharmaceutical excipients (∼50 total) were then evaluated to mitigate potency losses (measured through D-antigen ELISAs for IPV1, IPV2, and IPV3) during drying and storage. Various concentrations and combinations of stabilizing additives were optimized in terms of tIPV potency retention, and 2 candidate tIPV formulations containing cyclodextrin and a reducing agent (e.g., glutathione), maintained ≥80% D-antigen potency during drying and subsequent storage for 4 weeks at 4°C, and ≥60% potency for 3 weeks at room temperature with the majority of losses occurring within the first day of storage.