Related Experiment Video

Updated: Oct 22, 2025

Synthesis and Characterization of mRNA-Loaded PolyBeta Aminoesters Nanoparticles for Vaccination Purposes
08:27

Synthesis and Characterization of mRNA-Loaded PolyBeta Aminoesters Nanoparticles for Vaccination Purposes

Published on: August 13, 2021

4.7K

Protective activity of mRNA vaccines against ancestral and variant SARS-CoV-2 strains

Baoling Ying1, Bradley Whitener1, Laura A VanBlargan1

  • 1Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.

Biorxiv : the Preprint Server for Biology
|August 31, 2021
PubMed

Insights

mRNA vaccines offer COVID-19 protection, but waning immunity and variants like Delta can lead to breakthrough infections. Booster shots may be needed to maintain protection against SARS-CoV-2 variants.

Area of Science:

  • Immunology
  • Vaccinology
  • Virology

Background:

  • Waning immunity and emerging SARS-CoV-2 variants challenge the long-term efficacy of mRNA vaccines.
  • Assessing vaccine effectiveness against diverse viral strains and declining immune responses is crucial.

Approach:

  • Evaluated historical (mRNA-1273) and modified (mRNA-1273.351) Moderna mRNA vaccines in mouse models (129S2 and K18-hACE2).
  • Assessed immunogenicity (neutralizing antibodies, T cell responses) and protective activity against ancestral and variant SARS-CoV-2 strains.
  • Investigated effects of high and low vaccine doses, simulating waning immunity.

Key Points:

  • Both vaccine formulations induced neutralizing antibodies against SARS-CoV-2 variants, though responses were lower against the Delta variant.
  • High-dose vaccines provided protection against weight loss and lung pathology across all tested viruses.
  • Low-dose vaccines, mimicking waning immunity, showed breakthrough infections and pneumonia with the Delta variant.

Conclusions:

  • Declining mRNA vaccine immunity may increase susceptibility to breakthrough infections and disease with certain SARS-CoV-2 variants.
  • The findings underscore the potential need for additional booster immunizations to sustain protection.
  • Further research into variant-specific vaccine efficacy and optimal boosting strategies is warranted.

More Related Videos

Protocol for Recombinant RBD-based SARS Vaccines: Protein Preparation, Animal Vaccination and Neutralization Detection12:09

Protocol for Recombinant RBD-based SARS Vaccines: Protein Preparation, Animal Vaccination and Neutralization Detection

Published on: May 2, 2011

43.1K
Efficient Transfection of In vitro Transcribed mRNA in Cultured Cells Using Peptide-Poloxamine Nanoparticles10:16

Efficient Transfection of In vitro Transcribed mRNA in Cultured Cells Using Peptide-Poloxamine Nanoparticles

Published on: August 17, 2022

3.5K

Related Concept Videos

Viral Mutations00:36

Viral Mutations

A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material...
35.4K
Viruses with RNA Genomes01:29

Viruses with RNA Genomes

RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
251
Cancer Vaccines01:30

Cancer Vaccines

Cancer treatment vaccines are a rapidly evolving field that offers a promising approach to immunotherapy. Unlike traditional vaccines that prevent diseases, cancer treatment vaccines are designed to treat existing cancers by stimulating the immune system to recognize and attack cancer cells.
Cancer vaccines come in two categories: preventive (prophylactic) and treatment (active). Preventive vaccines, such as the Human Papillomavirus (HPV) vaccine, protect against viruses that cause certain...
570
Cross-reactivity00:42

Cross-reactivity

Overview
31.8K
Nuclear Export of mRNA02:31

Nuclear Export of mRNA

Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
8.0K
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R...
5.3K