ABSTRACT
The great challenge to prevent transmission makes widespread of respiratory infectious diseases easily occur. Intranasal immunization is considered to be a promising route of vaccination to prevent it. Different from parenteral vaccines, intranasal vaccines can induce mucosal immune in respiratory tracts in addition to systemic immune, which provide the first line of defense against respiratory pathogen infection and further prevent transmission. Safe and effective intranasal spray flu vaccines have been licensed. Since the outbreak of COVID-19, intranasal administration has been applied in different vaccine platforms. This article has reviewed the progress of intranasal vaccines for respiratory infectious diseases that have been licensed or are under evaluation in the clinical trials, meanwhile discusses its unique advantages and challenges faced. © 2023, Publication Centre of Anhui Medical University. All rights reserved.
ABSTRACT
The great challenge to prevent transmission makes widespread of respiratory infectious diseases easily occur. Intranasal immunization is considered to be a promising route of vaccination to prevent it. Different from parenteral vaccines, intranasal vaccines can induce mucosal immune in respiratory tracts in addition to systemic immune, which provide the first line of defense against respiratory pathogen infection and further prevent transmission. Safe and effective intranasal spray flu vaccines have been licensed. Since the outbreak of COVID-19, intranasal administration has been applied in different vaccine platforms. This article has reviewed the progress of intranasal vaccines for respiratory infectious diseases that have been licensed or are under evaluation in the clinical trials, meanwhile discusses its unique advantages and challenges faced.Copyright © 2023, Publication Centre of Anhui Medical University. All rights reserved.
ABSTRACT
OBJECTIVES: Asymptomatic patients, together with those with mild symptoms of coronavirus disease 2019 (COVID-19), may play an important role in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. However, the dynamics of virus shedding during the various phases of the clinical course of COVID-19 remains unclear at this stage. METHODS: A total of 18 patients found to be positive for SARS-CoV-2 infection by real-time reverse transcription PCR (RT-PCR) assay and admitted to Chongqing University Central Hospital between 29 January and 5 February 2020 were enrolled into this study. Medical data, pulmonary computed tomographic (CT) scan images and RT-PCR results were periodically collected during the patients' hospital stay. All participants were actively followed up for 2 weeks after discharge. RESULTS: A total of nine (50%) asymptomatic patients and nine (50%) patients with mild symptoms of COVID-19 were identified at admission. Six patients (66.7%) who were asymptomatic at admission developed subjective symptoms during hospitalization and were recategorized as being presymptomatic. The median duration of virus shedding was 11.5, 28 and 31 days for presymptomatic, asymptomatic and mildly symptomatic patients, separately. Seven patients (38.9%) continued to shed virus after hospital discharge. During the convalescent phase, detectable antibodies to SARS-CoV-2 and RNA were simultaneously observed in five patients (27.8%). CONCLUSIONS: Long-term virus shedding was documented in patients with mild symptoms and in asymptomatic patients. Specific antibody production to SARS-CoV-2 may not guarantee virus clearance after discharge. These observations should be considered when making decisions regarding clinical and public health, and when considering strategies for the prevention and control of SARS-CoV-2 infection.