Variants

Several variants of concern (VOCs) of SARS-CoV-2 are more infectious than the original Wuhan strain. It is therefore crucial to understand why in order to develop effective vaccines and other treatments. However, research is limited by the fact that SARS-CoV-2 must be handled in laboratories with level 3 of biosecurity (BSL-3). The majority of work […]

We are still witnessing the emergence of variants. The more the virus is transmitted, the greater the risk. In general, these variants possess a particular advantage: greater transmissibility or some capacity for evasion of immune responses. Variants that have already appeared include the Beta (South African), Gamma (Brazilian) and Alpha (UK): the latter became the […]

Despite the deployment of anti-COVID-19 vaccines in the 1st part of 2021, the number of cases and deaths linked to SARS-CoV-2 continued to increase in the northern hemisphere prior to the summer. The increase in cases was due in part to the emergence of the Delta (Indian) variant, which quickly became dominant at the expense […]

After several months of calm since the beginning of 2021, Israel has now seen the arrival of a 4th wave of the COVID-19 pandemic. However, more than 55% of the population were vaccinated between 5 and 7 months ago with 2 doses of the Pfizer-BioNTech mRNA vaccine. This undoubtedly means that immunity will now be […]

The Wuhan strain of SARS-CoV-2, from which the pandemic originated, has been used to develop currently available vaccines. Since its appearance, several variants have emerged, such as the Alpha (UK), Beta (South African), Gamma (Brazilian) and Delta (Indian). Amongst the molecules that make up SARS-CoV-2, the spike (S) is a key protein. It interacts on […]

The COVID-19 pandemic has constantly produced new variants, since SARS-CoV-2 adapts to humans by accumulating around 24 mutations per year. The first dominant mutation was D416G, which rendered this variant 20% more transmissible than the Wuhan ancestral strain. The B.1 lineage thus became established and spread rapidly throughout the world in April-May 2020. Since then, […]

India was not affectedly too badly at the beginning of the pandemic, but faced a much more severe crisis from April 2021. In the capital, Delhi, the virus had already been more widespread than in the rest of the country during the 1st wave, with more than 55% of inhabitants having been infected by January. […]

The first wave of SARS-CoV-2 infections in mid-2020 was more or less brought under control in India through a national lockdown. However, since March 2021, the country has experienced an explosion in cases due to the lifting of certain restrictions and the emergence of the Delta variant, at the end of 2020. This variant seemed […]

Recombination is a transfer of genetic material between two nucleic acid molecules (DNA or RNA). With respect to viruses, it can occur during the replication of the viral genome when an individual is co-infected by 2 strains of the virus. This process may generate a new variant, carrying a part of the genome of the […]

The Alpha (⍺) or UK variant emerged in England at the end of 2020 and spread rapidly throughout the country. By the 19 January 2021, this variant had reached all 4 countries of the UK. Despite travel restrictions, it then became dominant throughout the world. Studies have shown that this variant has higher transmissibility and […]