ABSTRACT
COVID-19 vaccines prevent severe forms of the disease, but do not warrant complete protection against breakthrough infections. This could be due to suboptimal mucosal immunity at the site of virus entry, given that all currently approved vaccines are administered via the intramuscular route. In this study, we assessed humoral and cellular immune responses in BALB/c mice after intranasal and intramuscular immunization with adenoviral vector ChAdOx1-S expressing full-length Spike protein of SARS-CoV-2. We showed that both routes of vaccination induced a potent IgG antibody response, as well as robust neutralizing capacity, but intranasal vaccination elicited a superior IgA antibody titer in the sera and in the respiratory mucosa. Bronchoalveolar lavage from intranasally immunized mice efficiently neutralized SARS-CoV-2, which has not been the case in intramuscularly immunized group. Moreover, substantially higher percentages of epitope-specific CD8 T cells exhibiting a tissue resident phenotype were found in the lungs of intranasally immunized animals. Finally, both intranasal and intramuscular vaccination with ChAdOx1-S efficiently protected the mice after the challenge with recombinant herpesvirus expressing the Spike protein. Our results demonstrate that intranasal application of adenoviral vector ChAdOx1-S induces superior mucosal immunity and therefore could be a promising strategy for putting the COVID-19 pandemic under control.
Subject(s)
COVID-19 , Viral Vaccines , Adenoviridae/genetics , Administration, Intranasal , Animals , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Immunity, Cellular , Immunity, Mucosal , Mice , Mice, Inbred BALB C , Pandemics/prevention & control , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Vaccination/methodsABSTRACT
During COVID-19 pandemics, the availability of testing has often been a limiting factor during patient admissions into the hospital. To circumvent this problem, we adapted an existing diagnostic assay, Seegene Allplex SARS-CoV-2, into a point-of-care-style direct qPCR (POC dqPCR) assay and implemented it in the Emergency Department of Clinical Hospital Center Rijeka, Croatia. In a 4-month analysis, we tested over 10,000 patients and demonstrated that POC-dqPCR is robust and reliable and can be successfully implemented in emergency departments and similar near-patient settings and can be performed by medical personnel with little prior experience in qPCR.