An S1 subunit vaccine and combination adjuvant (COVAC-1) elicits robust protection against SARS-CoV-2 challenge in African green monkeys
Bibliographic record
Abstract
ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent responsible for the ongoing global pandemic. With over 500 million cases and more than 6 million deaths reported globally, the need for access to effective vaccines is clear. An ideal SARS-CoV-2 vaccine will prevent pathology in the lungs and prevent virus replication in the upper respiratory tract, thus reducing transmission. Here, we assessed the efficacy of an adjuvanted SARS-CoV-2 S1 subunit vaccine, called COVAC-1, in an African green monkey (AGM) model. AGMs immunized and boosted with COVAC-1 were protected from SARS-CoV-2 challenge compared to unvaccinated controls based on reduced pathology and reduced viral RNA levels and infectious virus in the respiratory tract. Both neutralizing antibodies and antibodies capable of mediating antibody-dependent cell-mediated cytotoxicity (ADCC) were observed in vaccinated animals prior to the challenge. COVAC-1 induced effective protection, including in the upper respiratory tract, thus supporting further development and utility for determining the mechanism that confers this protection. AUTHOR SUMMARY Vaccines that can prevent the onward transmission of SARS-CoV-2 and prevent disease are highly desirable. Whether this can be accomplished without mucosal immunization by a parenterally administered subunit vaccine is not well established. Here we demonstrate that following two vaccinations, a protein subunit vaccine containing the S1 portion of the SARS-CoV-2 spike glycoprotein and the novel adjuvant TriAdj significantly reduces the amount of virus in the lungs and also mediates rapid clearance of the virus from the upper respiratory tract. Further support of the effectiveness of COVAC-1 was the observation of reduced pathology in the lungs and viral RNA being largely absent from tissues, blood, and rectal swabs. Thus COVAC-1 appears promising at mediating protection in both the upper and lower respiratory tract and may be capable of reducing subsequent transmission of SARS-CoV-2. Further investigation into the mechanism of protection in the upper respiratory tract and the initial immune response that supports this would be warranted.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".