A Review on Modern Use of Intranasal Vaccination in the Treatment of SARS-COV-2

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the urgent need for efficient SARS coronavirus 2 (SARS-CoV-2) preventative vaccines to limit the burden and spread of SARS-CoV-2 in humans. Intranasal immunization is a promising technique for preventing COVID-19 because the nasal mucosa acts as a first line of defense against SARS-CoV-2 entrance before the virus spreads to the lungs. Nasal vaccination has many advantages over traditional vaccine administration methods. These include the simplicity of administration without the use of needles, which decreases the risks of needle stick injuries and disposal. This channel also provides simple access to a crucial portion of the immune system that can stimulate other mucosal sites throughout the body. By targeting immunoglobulin A (IgA), antibodies found only in the mucosa, an intranasal vaccination would elicit immunological responses in the nose, throat, and lungs. Potential pathogens are trapped by the mucosa, which acts as a physical barrier to prevent them from entering the body. Given this, the intranasal vaccine would prevent virus transmission via exhaled droplets or aerosols because there would be no virus in the body to expel .There are several intranasal vaccines for protection against sars-cov2 are under preclinical and clinical trials .The key challenge is in Designing delivery strategies that take into account the wide range of diseases, populations, and healthcare delivery settings that stand to benefit from this unique mucosal route should be prioritized. Keywords: COVID-19, Intranasal vaccine, Immunoglobulin A, Permeation

Vaccination Route Determines the Kinetics and Magnitude of Nasal Innate Immune Responses in Rainbow Trout (Oncorhynchus mykiss)

Many pathogens infect animal hosts via the nasal route. Thus, understanding how vaccination stimulates early nasal immune responses is critical for animal and human health. Vaccination is the most effective method to prevent disease outbreaks in farmed fish. Nasal vaccination induces strong innate and adaptive immune responses in rainbow trout and was shown to be highly effective against infectious hematopoietic necrosis (IHN). However, direct comparisons between intranasal, injection and immersion vaccination routes have not been conducted in any fish species. Moreover, whether injection or immersion routes induce nasal innate immune responses is unknown. The goal of this study is to compare the effects of three different vaccine delivery routes, including intranasal (IN), intramuscular (i.m.) injection and immersion (imm) routes on the trout nasal innate immune response. Expression analyses of 13 immune-related genes in trout nasopharynx-associated lymphoid tissue (NALT), detected significant changes in immune expression in all genes analyzed in response to the three vaccination routes. However, nasal vaccination induced the strongest and fastest changes in innate immune gene expression compared to the other two routes. Challenge experiments 7 days post-vaccination (dpv) show the highest survival rates in the IN- and imm-vaccinated groups. However, survival rates in the imm group were significantly lower than the IN- and i.m.-vaccinated groups 28 dpv. Our results confirm that nasal vaccination of rainbow trout with live attenuated IHNV is highly effective and that the protection conferred by immersion vaccination is transient. These results also demonstrate for the first time that immersion vaccines stimulate NALT immune responses in salmonids.