Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are being deployed, but the global need greatly exceeds the supply, and different formulations might be required for specific populations. Here we report Day 42 interim safety and immunogenicity data from an observer-blinded, dose escalation, randomized controlled study of a virus-like particle vaccine candidate produced in plants that displays the SARS-CoV-2 spike glycoprotein (CoVLP: NCT04450004
 ). The co-primary outcomes were the short-term tolerability/safety and immunogenicity of CoVLP formulations assessed by neutralizing antibody (NAb) and cellular responses. Secondary outcomes in this ongoing study include safety and immunogenicity assessments up to 12 months after vaccination. Adults (18–55 years, n = 180) were randomized at two sites in Quebec, Canada, to receive two intramuscular doses of CoVLP (3.75 μg, 7.5 μg, and 15 μg) 21 d apart, alone or adjuvanted with AS03 or CpG1018. All formulations were well tolerated, and adverse events after vaccination were generally mild to moderate, transient and highest in the adjuvanted groups. There was no CoVLP dose effect on serum NAbs, but titers increased significantly with both adjuvants. After the second dose, NAbs in the CoVLP + AS03 groups were more than tenfold higher than titers in Coronavirus 2019 convalescent sera. Both spike protein-specific interferon-γ and interleukin-4 cellular responses were also induced. This pre-specified interim analysis supports further evaluation of the CoVLP vaccine candidate. Safety and immunogenicity results in humans of a two-dose SARS-CoV-2 vaccine made from plants support further assessment of potential efficacy.

/pdf/phase-1-randomized-trial-of-a-plant-derived-virus-like-10njumw7do.pdf

Phase 1 randomized trial of a plant-derived virus-like particle vaccine for COVID-19.

The extent to which immune responses to natural infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and immunization with vaccines protect against variants of concern (VOC) is of increasing importance. Accordingly, here we analyse antibodies and T cells of a recently vaccinated, UK cohort, alongside those recovering from natural infection in early 2020. We show that neutralization of the VOC compared to a reference isolate of the original circulating lineage, B, is reduced: more profoundly against B.1.351 than for B.1.1.7, and in responses to infection or a single dose of vaccine than to a second dose of vaccine. Importantly, high magnitude T cell responses are generated after two vaccine doses, with the majority of the T cell response directed against epitopes that are conserved between the prototype isolate B and the VOC. Vaccination is required to generate high potency immune responses to protect against these and other emergent variants.

/pdf/two-doses-of-sars-cov-2-vaccination-induce-robust-immune-zb6ui1kcuv.pdf

Two doses of SARS-CoV-2 vaccination induce robust immune responses to emerging SARS-CoV-2 variants of concern.

Comparative immunogenicity of mRNA and inactivated vaccines against COVID-19.

Does infection with or vaccination against SARS-CoV-2 lead to lasting immunity?

T helper type (Th1/Th2) responses to SARS-CoV-2 and influenza A (H1N1) virus: From cytokines produced to immune responses.

https://www.mdpi.com/2076-393X/9/3/238/pdf

Parichehr Shamsrizi

Papers

Correlates of Vaccine-Induced Protection against SARS-CoV-2.

Characterization of Individuals Interested in Participating in a Phase I SARS-CoV-2 Vaccine Trial.