PROTECTIVE EFFICACY of A GASTROINTESTINAL SARS-CoV-2 VACCINE
Topics in Antiviral Medicine
; 30(1 SUPPL):92-93, 2022.
Article
in English
| EMBASE | ID: covidwho-1881049
ABSTRACT
Background:
SARS-CoV-2 remains a global threat, despite the rapid deployment but limited coverage of multiple vaccines. Alternative vaccine strategies that have favorable manufacturing timelines, greater ease of distribution and improved coverage may offer significant public health benefits, especially in resource-limited settings. Live oral vaccines have the potential to address some of these limitations;however no studies have yet been conducted to assess the immunogenicity and protective efficacy of a live oral vaccine against SARS-CoV-2. Thus far, we assessed whether oral administration of live SARS-CoV-2 in non-human primates might offer prophylactic benefits.Methods:
In this study, we assessed the immunogenicity of gastrointestinal (GI) delivery of SARS-CoV-2 and the protective efficacy against intranasal and intratracheal SARS-CoV-2 challenge in rhesus macaques. Esophagogastroduodenoscopy (EGD) administration of 106 50% Tissue Culture Infectious Dose (TCID50) of SARS-CoV-2 elicited low levels of serum neutralizing antibodies (NAb), which correlated with modestly diminished viral loads in nasal swabs (NS) and Bronchoalveolar Lavage (BAL) post-challenge. In addition, mucosal NAb titers from the rectal swabs (RS), NS, and BAL and Spike-specific T-cell responses appear to be below the limit of detection post-vaccination. Replicating virus was only observed in 44% of macaques and on limited number of dates post vaccination, suggesting limited, if any, productive infection in the GI tract.Results:
We demonstrate that GI delivery of live 1x106 TCID50 SARS-CoV-2 elicited modest immune responses and provided partial protection against intranasal and intratracheal challenge with SARS-CoV-2. Moreover, serum neutralizing antibody titers correlated with protective efficacy.Conclusion:
These data provide proof-of-concept that an orally administered vaccine can protect against respiratory SARS-CoV-2 challenge, but the limited immunogenicity and protective efficacy observed here suggests that the oral vaccine approach will require optimization.
neutralizing antibody; SARS-CoV-2 vaccine; animal experiment; animal model; animal tissue; conference abstract; controlled study; esophagogastroduodenoscopy; gastrointestinal infection; human; immune response; immunogenicity; limit of detection; lung lavage; nonhuman; nose smear; oral drug administration; proof of concept; rectal swab; rhesus monkey; Severe acute respiratory syndrome coronavirus 2; spike; T lymphocyte; TCID50; vaccination; virus load
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Collection:
Databases of international organizations
Database:
EMBASE
Topics:
Vaccines
Language:
English
Journal:
Topics in Antiviral Medicine
Year:
2022
Document Type:
Article
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