Related Experiment Video
Updated: Oct 19, 2025
08:41
Live Imaging and Quantification of Viral Infection in K18 hACE2 Transgenic Mice Using Reporter-Expressing Recombinant SARS-CoV-2
Published on: November 5, 2021
3.0K
[COVID-19: epidemiology and mutations : An update]
Christoph J Hemmer1, M Löbermann2, E C Reisinger2
1Abteilung für Tropenmedizin und Infektionskrankheiten, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 5, 18057, Rostock, Deutschland. Christoph.Hemmer@uni-rostock.de.
Der Radiologe
|September 20, 2021
Summary
Mutations in SARS-CoV-2 variants like Delta increase infectiousness and reduce vaccine effectiveness against mild illness. However, vaccination remains crucial, offering strong protection against severe disease and death.
Area of Science:
- Virology
- Immunology
- Epidemiology
Background:
- Mutations in SARS-CoV-2 can increase transmissibility and immune evasion.
- Emerging variants like Alpha, Beta, Gamma, and Delta pose significant public health challenges.
- Understanding variant impact on vaccine effectiveness and disease severity is critical.
Purpose of the Study:
- To analyze the impact of SARS-CoV-2 variants on infectiousness and antibody effectiveness.
- To evaluate the effectiveness of available vaccines against different SARS-CoV-2 variants.
- To assess the severity and mortality risks associated with key SARS-CoV-2 variants.
Main Methods:
- Review of scientific literature on SARS-CoV-2 variants and vaccine effectiveness.
- Comparative analysis of variant characteristics, including transmissibility and immune escape.
- Examination of vaccine efficacy data against different variants.
Main Results:
- Alpha variant increased infectiousness by 75%; vaccine effectiveness slightly reduced.
- Beta variant decreased antibody neutralization; some vaccines showed minimal protection.
- Gamma variant showed increased transmissibility and mortality risk.
- Delta variant is 50% more infectious than Alpha, with reduced vaccine protection against symptomatic disease but still good protection against severe outcomes.
- Vaccinated individuals experience less severe disease and lower mortality with the Delta variant.
Conclusions:
- High vaccination rates are essential for achieving herd immunity and controlling the pandemic.
- While some vaccines show reduced efficacy against mild illness from variants, they maintain strong protection against severe and fatal disease.
- Continued monitoring of SARS-CoV-2 variants and vaccine effectiveness is necessary.
Related Concept Videos
00:36Viral Mutations
35.2K
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...
35.2K
01:18Mutations in Microorganisms
182
Mutations are heritable changes in an organism’s genome involving alterations in the base sequence of DNA or RNA. These changes can influence cellular processes and phenotypic traits, potentially transforming the unaltered wild type into a mutant form. Such changes, termed forward mutations, are pivotal in shaping the genetic diversity of organisms.RNA viruses exhibit the highest mutation rates due to the absence of robust proofreading mechanisms during genome replication. In contrast,...
182
01:05Single Nucleotide Polymorphisms-SNPs
16.8K
A single nucleotide polymorphism or SNP is a single nucleotide variation at a specific genomic position in a large population. It is the most prevalent type of sequence variation found in the human genome. Point mutations that occur in more than 1% of the population qualify as SNPs. These are present once every 1000 nucleotides on an average in the human genome. Replacement of a purine with another purine (A/G) or a pyrimidine with another pyrimidine (C/T) is known as a transition. In contrast,...
16.8K
01:39Mutations
85.8K
Overview
85.8K
01:30Spontaneous and Induced Mutations
339
Spontaneous mutations arise infrequently during DNA replication due to errors in the process. A key factor behind these errors is tautomeric shifts in nitrogenous bases, where bases transition from keto to enol forms or amino to imino forms. This shift can alter base-pairing rules, leading to mutations. Additionally, reactive oxygen species (ROS) arising from aerobic metabolism can damage DNA, resulting in depurination (loss of a purine base) or depyrimidination (loss of a pyrimidine base).
339
01:09Mutation, Gene Flow, and Genetic Drift
60.1K
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).
60.1K