1
|
Tedjakusuma SN, Lester CA, Neuhaus ED, Dora EG, Gutierrez S, Braun MR, Tucker SN, Flitter BA. A Next-Generation Adenoviral Vaccine Elicits Mucosal and Systemic Immunogenicity and Reduces Viral Shedding after SARS-CoV-2 Challenge in Nonhuman Primates. Vaccines (Basel) 2024; 12:132. [PMID: 38400116 PMCID: PMC10893453 DOI: 10.3390/vaccines12020132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 01/20/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
As new SARS-CoV-2 variants continue to emerge and impact communities worldwide, next-generation vaccines that enhance protective mucosal immunity may have a significant impact on productive infection and transmission. We have developed recombinant non-replicating adenovirus serotype 5 (rAd5) vaccines delivered by mucosal administration that express both target antigen and a novel molecular adjuvant within the same cell. Here, we describe the immunogenicity of three unique SARS-CoV-2 rAd5 vaccine candidates and their efficacy following viral challenge in non-human primates (NHPs). Intranasal immunization with rAd5 vaccines expressing Wuhan, or Beta variant spike alone, or Wuhan spike and nucleocapsid elicited strong antigen-specific serum IgG and IgA with neutralizing activity against multiple variants of concern (VOC). Robust cross-reactive mucosal IgA was detected after a single administration of rAd5, which showed strong neutralizing activity against multiple VOC. Additionally, mucosal rAd5 vaccination increased spike-specific IFN-γ producing circulating T-cells. Upon Beta variant SARS-CoV-2 challenge, all the vaccinated NHPs exhibited significant reductions in viral load and infectious particle shedding in both the nasal passages and lower airways. These findings demonstrate that mucosal rAd5 immunization is highly immunogenic, confers protective cross-reactive antibody responses in the circulation and mucosa, and reduces viral load and shedding after SARS-CoV-2 challenge.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Becca A. Flitter
- Vaxart, Inc., South San Francisco, CA 94080, USA; (S.N.T.); (C.A.L.); (E.D.N.); (E.G.D.); (S.G.); (M.R.B.); (S.N.T.)
| |
Collapse
|
2
|
Braun MR, Flitter BA, Sun W, Tucker SN. An easy pill to swallow: oral recombinant vaccines for the 21st century. Curr Opin Immunol 2023; 84:102374. [PMID: 37562075 DOI: 10.1016/j.coi.2023.102374] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 08/12/2023]
Abstract
Oral vaccines have a distinctive advantage of stimulating immune responses in the mucosa, where numerous pathogens gain entry and cause disease. Although various efforts have been attempted to create recombinant mucosal vaccines that provoke strong immunogenicity, the outcomes in clinical trials have been weak or inconsistent. Therefore, next-generation mucosal vaccines are needed that are more immunogenic. Here, we discuss oral vaccines with an emphasis on a next-generation mucosal vaccine that utilizes a nonreplicating human recombinant adenovirus type-5 (rAd5) vector. Numerous positive clinical results investigating oral rAd5 vaccines are reviewed, with a summary of the immunogenicity and efficacy results for specific vaccine indications of influenza, norovirus, and SARS-CoV-2. The determination of correlates of protection for oral vaccination and the potential impact this novel vaccine formulation may have on disease transmission are also discussed. In summary, successful oral vaccination can be accomplished and would have major public health benefits if approved.
Collapse
Affiliation(s)
- Molly R Braun
- Vaxart, Inc., 170 Harbor Way STE 300, South San Francisco, CA 94080, USA
| | - Becca A Flitter
- Vaxart, Inc., 170 Harbor Way STE 300, South San Francisco, CA 94080, USA
| | - William Sun
- Vaxart, Inc., 170 Harbor Way STE 300, South San Francisco, CA 94080, USA
| | - Sean N Tucker
- Vaxart, Inc., 170 Harbor Way STE 300, South San Francisco, CA 94080, USA.
| |
Collapse
|
3
|
Kwong KWY, Xin Y, Lai NCY, Sung JCC, Wu KC, Hamied YK, Sze ETP, Lam DMK. Oral Vaccines: A Better Future of Immunization. Vaccines (Basel) 2023; 11:1232. [PMID: 37515047 PMCID: PMC10383709 DOI: 10.3390/vaccines11071232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Oral vaccines are gaining more attention due to their ease of administration, lower invasiveness, generally greater safety, and lower cost than injectable vaccines. This review introduces certified oral vaccines for adenovirus, recombinant protein-based, and transgenic plant-based oral vaccines, and their mechanisms for inducing an immune response. Procedures for regulatory approval and clinical trials of injectable and oral vaccines are also covered. Challenges such as instability and reduced efficacy in low-income countries associated with oral vaccines are discussed, as well as recent developments, such as Bacillus-subtilis-based and nanoparticle-based delivery systems that have the potential to improve the effectiveness of oral vaccines.
Collapse
Affiliation(s)
- Keith Wai-Yeung Kwong
- Research Department, DreamTec Cytokines Limited, Hong Kong, China
- Oristry BioTech (HK) Limited, Hong Kong, China
- Theratide BioTech (HK) Limited, Hong Kong, China
| | - Ying Xin
- Research Department, DreamTec Cytokines Limited, Hong Kong, China
| | - Nelson Cheuk-Yin Lai
- Research Department, DreamTec Cytokines Limited, Hong Kong, China
- Oristry BioTech (HK) Limited, Hong Kong, China
- Theratide BioTech (HK) Limited, Hong Kong, China
| | - Johnny Chun-Chau Sung
- Research Department, DreamTec Cytokines Limited, Hong Kong, China
- Oristry BioTech (HK) Limited, Hong Kong, China
- Theratide BioTech (HK) Limited, Hong Kong, China
| | - Kam-Chau Wu
- Research Department, DreamTec Cytokines Limited, Hong Kong, China
| | | | - Eric Tung-Po Sze
- School of Science and Technology, Hong Kong Metropolitan University, Hong Kong, China
| | - Dominic Man-Kit Lam
- DrD Novel Vaccines Limited, Hong Kong, China
- Torsten Wiesel International Research Institute, Sichuan University, Chengdu 610064, China
| |
Collapse
|
4
|
Braun MR, Martinez CI, Dora EG, Showalter LJ, Mercedes AR, Tucker SN. Mucosal immunization with Ad5-based vaccines protects Syrian hamsters from challenge with omicron and delta variants of SARS-CoV-2. Front Immunol 2023; 14:1086035. [PMID: 36911687 PMCID: PMC9992185 DOI: 10.3389/fimmu.2023.1086035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/08/2023] [Indexed: 02/24/2023] Open
Abstract
SARS-CoV-2 variant clades continue to circumvent antibody responses elicited by vaccination or infection. Current parenteral vaccination strategies reduce illness and hospitalization, yet do not significantly protect against infection by the more recent variants. It is thought that mucosal vaccination strategies may better protect against infection by inducing immunity at the sites of infection, blocking viral transmission more effectively, and significantly inhibiting the evolution of new variants of concern (VOCs). In this study, we evaluated the immunogenicity and efficacy of a mucosally-delivered, non-replicating, adenovirus type 5-vectored vaccine that expresses the spike (S) gene of Wuhan (rAd5-S-Wuhan), delta (rAd5-S-delta), or omicron (rAd5-S-omicron) SARS-CoV-2 VOCs. Hamsters were immunized with these vaccines intranasally prior to challenge with omicron or delta variants. Additionally, one group was vaccinated by oral gavage with rAd5-S-Wuhan prior to challenge with the delta variant. Both intranasal and oral administration of rAd5-S-Wuhan generated cross-reactive serum IgG and mucosal IgA to all variant spike and RBD proteins tested. rAd5-S-omicron and rAd5-S-delta additionally elicited cross-reactive antibodies, though rAd5-S-omicron had significantly lower binding antibody levels except against its matched antigens. Two weeks after the final vaccination, hamsters were challenged with a SARS-CoV-2 variant; omicron or delta. Whether matched to the challenge or with rAd5-S-Wuhan, all vaccines protected hamsters from weight loss and lung pathology caused by challenge and significantly reduced viral shedding compared to placebo. Vaccination with rAd5-S-Wuhan provided significant protection, although there was an improved reduction in shedding and disease pathology in groups protected by the matched VOC vaccines. Nevertheless, Wuhan-based vaccination elicited the most cross-reactive antibody responses generally. Overall, heterologous vaccination via mucosal routes may be advantageous for second-generation vaccines.
Collapse
Affiliation(s)
- Molly R Braun
- Research & Development, Vaxart, Inc., South San Francisco, CA, United States
| | - Clarissa I Martinez
- Research & Development, Vaxart, Inc., South San Francisco, CA, United States
| | - Emery G Dora
- Research & Development, Vaxart, Inc., South San Francisco, CA, United States
| | - Laura J Showalter
- Research & Development, Vaxart, Inc., South San Francisco, CA, United States
| | - Annette R Mercedes
- Research & Development, Vaxart, Inc., South San Francisco, CA, United States
| | - Sean N Tucker
- Research & Development, Vaxart, Inc., South San Francisco, CA, United States
| |
Collapse
|
5
|
Lai F, Li X, Liu T, Wang X, Wang Q, Chen S, Wei S, Xiong Y, Hou Q, Zeng X, Yang Y, Li Y, Lin Y, Yang X. Optimal diagnostic fever thresholds using non-contact infrared thermometers under COVID-19. Front Public Health 2022; 10:985553. [PMID: 36504995 PMCID: PMC9730337 DOI: 10.3389/fpubh.2022.985553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/08/2022] [Indexed: 11/25/2022] Open
Abstract
Fever screening is an effective method to detect infectors associated with different variants of coronavirus disease 2019 (COVID-19) based on the fact that most infectors with COVID-19 have fever symptoms. Non-contact infrared thermometers (NCITs) are widely used in fever screening. Nevertheless, authoritative data is lacking in defining "fever" at different body surface sites when using NCITs. The purpose of this study was to determine the optimal diagnostic threshold for fever screening using NICTs at different body surface sites, to improve the accuracy of fever screening and provide theoretical reference for healthcare policy. Participants (n = 1860) who were outpatients or emergency patients at Chengdu Women's and Children's Central Hospital were recruited for this prospective investigation from March 1 to June 30, 2021. NCITs and mercury axillary thermometers were used to measure neck, temple, forehead and wrist temperatures of all participants. Receiver operating characteristic curves were used to reflect the accuracy of NCITs. Linear correlation analysis was used to show the effect of age on body temperature. Multilinear regression analysis was used to explore the association between non-febrile participant's covariates and neck temperature. The mean age of participants was 3.45 ± 2.85 years for children and 28.56 ± 7.25 years for adults. In addition 1,304 (70.1%) participants were children (≤12), and 683 (36.7%) were male. The neck temperature exhibited the highest accuracy among the four sites. Further the optimal fever diagnostic thresholds of NCITs at the four body surface measurement sites were neck (36.75 °C, sensitivity: 0.993, specificity: 0.858); temple (36.55 °C, sensitivity: 0.974, specificity: 0.874); forehead (36.45 °C, sensitivity: 0.961, specificity: 0.813); and wrist (36.15 °C, sensitivity: 0.951, specificity: 0.434). Based on the findings of our study, we recommend 36.15, 36.45, 36.55, and 36.75 °C as the diagnostic thresholds of fever at the wrist, forehead, temple and neck, respectively. Among the four surface sites, neck temperature exhibited the highest accuracy.
Collapse
Affiliation(s)
- Fan Lai
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xin Li
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Tianjiao Liu
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xin Wang
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Qi Wang
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Shan Chen
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Sumei Wei
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Ying Xiong
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Qiannan Hou
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xiaoyan Zeng
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yang Yang
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yalan Li
- Psychiatry Department, The Fourth People's Hospital of Chengdu, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,*Correspondence: Yalan Li
| | - Yonghong Lin
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,Yonghong Lin
| | - Xiao Yang
- Obstetrics Department, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,Xiao Yang
| |
Collapse
|