Vandeputte J, Van Damme P, Neyts J, Audonnet JC, Baay M, Neels P. Animal experiments show impact of vaccination on reduction of SARS-CoV-2 virus circulation: A model for vaccine development?
Biologicals 2021;
73:1-7. [PMID:
34489162 PMCID:
PMC8414133 DOI:
10.1016/j.biologicals.2021.08.001]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND
In the pre-clinical phase, SARS-CoV-2 vaccines were tested in animal models, including exposure trials, to investigate protection against SARS-CoV-2. These studies paved the way for clinical development. The objective of our review was to provide an overview of published animal exposure results, focussing on the capacity of vaccines to reduce/prevent viral shedding.
METHOD
Using Medline, we retrieved eighteen papers on eight different vaccine platforms in four animal models. Data were extracted on presence/absence of viral RNA in nose, throat, or lungs, and neutralizing antibody levels in the blood.
RESULTS
All vaccines showed a tendency of reduced viral load after exposure. Particularly nasal swab results are likely to give an indication about the impact on virus excretion in the environment. Similarly, the reduction or prevention of viral replication in the bronchoalveolar environment might be related with disease prevention, explaining the high efficacy in clinical trials.
DISCUSSION
Although it remains difficult to compare the results directly, the potential for a strong reduction of transmission was shown, indicating that the animal models predicted what is observed in the field after large scale human vaccination. This merits further attention for standardization of exposure experiments, with the intention to speed up future vaccine development.
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