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1.
Journal of the Formosan Medical Association ; 2022.
Article in English | ScienceDirect | ID: covidwho-2007843

ABSTRACT

Background /Purpose: The efficacy and safety of coronavirus disease 2019 (COVID-19) booster vaccines remain limited. We investigated the immunogenicity and adverse events of the third dose of mRNA vaccines in healthy adults. Methods Volunteers vaccinated with two doses of the adenoviral vaccine (ChAdOx1) 12 weeks before were administered with an mRNA COVID-19 vaccine. These were divided into three groups, full-dose mRNA-1273 (group 1);half-dose mRNA-1273 (group 2);and full-dose BNT-162b2 (group 3). Primary outcomes included serum anti-SARS-CoV-2 spike immunoglobulin G (IgG) titers and neutralizing antibody titers against B.1.1.7 (alpha), B.1.617.2 (delta), and B.1.1.529 (omicron) variants. Secondary outcomes included the evaluation of humoral and cellular immunity and vaccine-associated adverse events after the boost. Results Totally 300 participants were recruited, and 298 participants were enrolled. For all three groups, an increase in anti-SARS-CoV-2 spike IgG geometric mean titers (30.12- to 71.81-fold) and neutralizing antibody titers against the alpha variant (69.77- to 173.2-folds), delta variant (132.68- to 324.73-folds), and omicron variant (135.4- to 222.4-folds) were observed on day 28. All groups showed robust T- and B-cell responses after boosting. Adverse events were overall mild and transient but with higher prevalence and severity in group 1 participants than in other groups. Conclusions Third dose mRNA COVID-19 vaccines markedly enhanced cellular and humoral responses and were safe. Immunological responses and adverse events were higher in individuals receiving the full-dose mRNA-1273 vaccine, followed by a half-dose mRNA-1273 vaccine and BNT-162b2 vaccine.

2.
J Formos Med Assoc ; 121(4): 766-777, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1882193

ABSTRACT

BACKGROUND/PURPOSE: Efficacy and safety data of heterologous prime-boost vaccination against SARS-CoV-2 remains limited. METHODS: We recruited adult volunteers for homologous or heterologous prime-boost vaccinations with adenoviral (ChAdOx1, AstraZeneca) and/or mRNA (mRNA-1273, Moderna) vaccines. Four groups of prime-boost vaccination schedules were designed: Group 1, ChAdOx1/ChAdOx1 8 weeks apart; Group 2, ChAdOx1/mRNA-1273 8 weeks apart; Group 3, ChAdOx1/mRNA-1273 4 weeks apart; and Group 4, mRNA-1273/mRNA-1273 4 weeks apart. The primary outcome was serum anti-SARS-CoV-2 IgG titers and neutralizing antibody titers against B.1.1.7 (alpha) and B.1.617.2 (delta) variants on day 28 after the second dose. Adverse events were recorded up until 84 days after the second dose. RESULTS: We enrolled 399 participants with a median age of 41 years and 75% were female. On day 28 after the second dose, the anti-SARS-CoV-2 IgG titers of both heterologous vaccinations (Group 2 and Group 3) were significantly higher than that of homologous ChAdOx1 vaccination (Group 1), and comparable with homologous mRNA-1273 vaccination (Group 4). The heterologous vaccination group had better neutralizing antibody responses against the alpha and delta variant as compared to the homologous ChAdOx1 group. Most of the adverse events (AEs) were mild and transient. AEs were less frequent when heterologous boosting was done at 8 weeks rather than at 4 weeks. CONCLUSION: Heterologous ChAdOx1/mRNA-1273 vaccination provided higher immunogenicity than homologous ChAdOx1 vaccination and comparable immunogenicity with the homologous mRNA-1273 vaccination. Our results support the safety and efficacy of heterologous prime-boost vaccination using the ChAdOx1 and mRNA-1273 COVID-19 vaccines. (ClinicalTrials.gov number, NCT05074368).


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Female , Humans , Immunity , Vaccination
3.
Clin Infect Dis ; 73(9): e2960-e2961, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1501029

Subject(s)
COVID-19 , SARS-CoV-2 , Humans
4.
Mol Ther Methods Clin Dev ; 21: 299-314, 2021 Jun 11.
Article in English | MEDLINE | ID: covidwho-1144097

ABSTRACT

Antigen-specific lung-resident memory T cells (TRMs) constitute the first line of defense that mediates rapid protection against respiratory pathogens and inspires novel vaccine designs against infectious pandemic threats, yet effective means of inducing TRMs, particularly via non-viral vectors, remain challenging. Here, we demonstrate safe and potent induction of lung-resident TRMs using a biodegradable polymeric nanoshell that co-encapsulates antigenic peptides and TLR9 agonist CpG-oligodeoxynucleotide (CpG-ODN) in a virus-mimicking structure. Through subcutaneous priming and intranasal boosting, the combinatorial nanoshell vaccine elicits prominent lung-resident CD4+ and CD8+ T cells that surprisingly show better durability than live viral infections. In particular, nanoshells containing CpG-ODN and a pair of conserved class I and II major histocompatibility complex-restricted influenza nucleoprotein-derived antigenic peptides are demonstrated to induce near-sterilizing immunity against lethal infections with influenza A viruses of different strains and subtypes in mice, resulting in rapid elimination of replicating viruses. We further examine the pulmonary transport dynamic and optimal composition of the nanoshell vaccine conducive for robust TRM induction as well as the benefit of subcutaneous priming on TRM replenishment. The study presents a practical vaccination strategy for inducing protective TRM-mediated immunity, offering a compelling platform and critical insights in the ongoing quest toward a broadly protective vaccine against universal influenza as well as other respiratory pathogens.

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