The intradermal vaccination route – an attractive opportunity for influenza vaccination in the elderly

Older adults: panoramic view on the COVID-19 vaccination

In December 2020, COVID-19 vaccination started in many countries, with which the world community hopes to stop the further spread of the current pandemic. More than 90% of sick and deceased patients belong to the category of older adults (65 years and older). This category of the population is most vulnerable to infectious diseases, so vaccination is the most effective preventive strategy, the need for which for older adults is indisputable. Here we briefly summarize information about age-related changes in the immune system and present current data on their impact on the formation of the immune response to vaccination. Older age is accompanied by the process of biological aging accompanied by involution of the immune system with increased susceptibility to infections and a decrease in the effect of immunization. Therefore, in the ongoing mass COVID-19 vaccination, the older adults are a growing public health concern. The authors provide an overview of the various types of COVID-19 vaccines approved for mass immunization of the population by the end of 2020, including older adults, as well as an overview of strategies and platforms to improve the effectiveness of vaccination of this population. In the final part, the authors propose for discussion a system for assessing the safety and monitoring the effectiveness of COVID-19 vaccines for the older adults.

Host responses in human skin after conventional intradermal injection or microneedle administration of virus-like-particle influenza vaccine

Miniaturized microneedle devices are being developed for painlessly targeting vaccines to the immune cell populations in skin. As skin immunization studies are generally restricted to animal models however, where skin architecture and immunity is greatly different to human, surprisingly little is known about the local human response to intradermal (ID) vaccines. Here surgically excised human skin is used to explore for the first time the complex molecular and cellular host responses to a candidate influenza vaccine comprising nanoparticulate virus-like-particles (VLPs), administered via conventional hypodermic injection or reduced scale microneedles. Responses at the molecular level are determined by microarray analysis (47,296 discrete transcripts) and validated by quantitative PCR (96 genes). Cellular response is probed through monitoring migration of dendritic cells in viable skin tissue. Gene expression mapping, ontological analysis, and qPCR reveal up-regulation of a host of genes responsible for key immunomodulatory processes and host viral response, including cell recruitment, activation, migration, and T cell interaction following both ID and microneedle injection of VLPs; the response from the microneedles being more subtle. Significant morphological and migratory changes to skin dendritic cells are also apparent following microneedle VLP delivery. This is the first study displaying the global, multifaceted immunological events that occur at the site of vaccine deposition in human skin and will subsequently influence the degree and nature of innate and adaptive immune responses. An increased understanding of the detailed similarities and differences in response against antigen administered via different delivery modalities will inform the development of improved vaccines and vaccine delivery systems.

Immunosenescence and herd immunity: with an ever-increasing aging population do we need to rethink vaccine schedules?

Vaccination is a powerful public health tool that has been of tremendous benefit in protecting vulnerable populations from specific infections. Moreover, in addition to the direct benefits to vaccinated individuals, the indirect effects of protection at the community level have also been demonstrated and termed 'herd immunity'. The predicted demographic shift in the population landscape towards an ever-increasing aging population and the evidence suggesting that older individuals produce less-than-optimal vaccine responses have raised the question of rethinking vaccine schedules. This article provides evidence that even if herd immunity might be an option to indirectly protect the aging and aged adult population, the highest priorities for the near future must be to understand how vaccine responses in older individuals can be improved, to break down the public, cultural, societal and political barriers to vaccination and to counter the antivaccination movement that inhibits the worldwide spread of lifelong immunization programs.

The use of STOPP/START criteria as a screening tool for assessing the appropriateness of medications in the elderly population

Although numerous initiatives and interventions have been developed to promote medication safety, medication incidents still remain an important cause of hospitalization. To avoid this, it is important for physicians to prescribe safely. To date, the Beers criteria have been the most widely used explicit criteria for assessing the appropriateness of medications in the elderly, but they do have limitations. The more recent STOPP/START criteria were developed in the hope of addressing the deficiencies observed in the Beers criteria. This article gives an overview of STOPP/START criteria and its applications, and reviews the studies that assessed medication appropriateness using STOPP/START and/or the Beers criteria.

An update on the application of physical technologies to enhance intradermal and transdermal drug delivery

A large number of biopharmaceuticals and other macromolecules are being developed for therapeutic applications. Conventional oral delivery is not always possible due to first-pass metabolism and degradation in the GI tract. Parenteral delivery is invasive and has poor patient compliance. Transdermal delivery provides one attractive route of administration. Transdermal administration can achieve the continuous and non-invasive delivery of drugs. However, passive transdermal delivery is restricted to small lipophilic molecules. Active physical-enhancement technologies are being investigated to increase the scope of transdermal delivery to hydrophilic molecules and macromolecules. Recent developments in transdermal technologies, such as microporation, iontophoresis and sonophoresis can enable therapeutic delivery of many drug molecules, biopharmaceuticals, cosmeceuticals and vaccines. This review provides an update of recent developments in transdermal delivery focusing on physical-enhancement technologies.