Inhaled vaccine delivery in the combat against respiratory viruses: a 2021 overview of recent developments and implications for COVID-19

Abstract

Introduction: As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care. Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses. Areas covered: Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy. We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible. The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar. Expert opinion: We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages. Firstly, their dry state can tremendously increase vaccine stability and shelf-life. Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns. Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.

The future of dry powder inhaled therapy: Promising or discouraging for systemic disorders?

“…4) single-use prevision only , not requiring frequent and continuous dosing under most conditions ( Heida et al, 2021 )– ( “Disposable DPI,” Manta Devices Inhaler. https://mantadevices.com/dry-powder-inhaler-development/disposable-dpi/ (accessed Jul.…”

“…03, 2021 ). Until now, single-use DPI systems for vaccination use have not been widely utilized with regulatory approval but some products for non-COVID uses have reached the clinical phase ( Heida et al, 2021 ). Two potential disposable DPIs for vaccines are presented in Figure8 .…”

“…23, 2021). The Solovent system (Becton, Dickinson and Co.) was principally developed to deliver powder-form vaccines into the lungs or nasal cavity through a single inhalation (“Solo Vent”) ( Heida et al, 2021 ). It uses a syringe to pressurize the powered vaccine contained in the capsule as shown in Figure8 B.…”

Emerging Advances of Nanotechnology in Drug and Vaccine Delivery against Viral Associated Respiratory Infectious Diseases (VARID)

“…DiagNano™, a silica magnetic nanoparticle, is designed as an anti-human IgA, IgG, IgM conjugated nanoparticle formulated for rapid test diagnostic kits and can be used for other clinical approaches. PreveCeutical ® , as a SiO 2 sol-gel delivery platform, is an FDA approved nanoparticle used for nose-to-brain drug delivery [69] (63). The most effective vaccine routes in the COVID-19 pandemic may be inhaled vaccines, as this type of vaccine produces very powerful mucosal dimeric IgA that can block the virus entry in the first line of infection defense [70,71].…”

Efficacy versus abundancy: which vaccination schemes can better prohibit deaths and active infections?

“…By August 23, 2021, a total of about 4.97 billion doses of those vaccines were administered with main concentration in China, USA, India and Europe [21]. Other vaccines, inhaled aerosol dry vaccines and antiviral drugs are under extensive research and development [22, 23, 24]. Antibody therapies are under development as well and they offer an effective treatment for the most seriously ill patients, but they remain expensive and in short supply [25].…”