The emergence of variants of concern (VOC), different to the original Wuhan strain from both antigenic and functional points of view, call into question the efficacy of current vaccines, since they may be able to evade neutralising antibodies (nAbs). In particular, the Alpha (⍺) or UK variant, the Gamma (ɣ) or Brazilian variant, the Beta […]

The SARS-CoV-2 variants of concern (VOC) are more transmissible, potentially more virulent, and capable of escaping neutralising antibodies (nAbs), whether they are therapeutic or induced by natural infection or by vaccination. The spike governs viral entry, and is composed, amongst other elements, of the RBD (receptor binding domain), which interacts with the human ACE2 receptor. […]

The majority of adults in the West are now vaccinated. This is the case in, for example, more than half of the adult population in the United States. Here, several preventative health measures, such as mask wearing and social distancing, have been relaxed to enable a return to near-normal life. However, the 10 to 30% […]

Numerous SARS-CoV-2 variants have appeared over recent months, including the Californian or Epsilon (ε) variant. This new strain emerged at the beginning of 2021 in California, and had been detected in more than 34 countries, including France, by May. The spike surface protein of this variant carries the L452R mutation in the RBD (the region […]

SARS-CoV-2 has infected more millions of  people. Brazil has been the most affected country with more than 15 million cases and more than 430 000 deaths. Vaccines have allowed us to greatly reduce mortality rates, and amongst available vaccines, the CoronaVac (also called Sinovac), developed in China, is the only one to use the traditional technology of […]

Severe cases of COVID-19 result in uncontrolled inflammation leading to thrombosis (formation of blood clots) in several organs. These risks are generally assessed by levels of specific circulating biomarkers, such as C-reactive protein or D-dimer. As a precaution, patients may be given preventative treatments based on heparin and low molecular weight derivatives (pharmacological thromboprophylaxis), in […]

The mutation rate of SARS-CoV-2 is relatively low due to its correcting activity during genome replication. However, its high rate of replication and its high transmissibility lead to the rapid emergence of variants. Amongst those that have emerged, the Alpha (a) or UK variant quickly became dominant. The Beta (b) or South African variant also […]

Since the beginning of the COVID-19 pandemic, a number of variants of SARS-CoV-2 have appeared. Amongst them are variants of concern, (VOC), which have acquired several biological advantages: better transmissibility, increased virulence, resistance to neutralising antibodies acquired through vaccination or by natural infection, and the ability to evade treatments and some detection methods. These properties […]

When a sufficiently large percentage of a population is immunised against a pathogen, this latter can no longer cause large-scale epidemics. Immunity may be acquired through vaccination, or natural infection. What are the practical issues involved in attaining it? In the absence of vaccination, and if immunity is long-lasting and has a sterilising effect (absence […]

Vaccines have been a vital part of eradicating or controlling several deadly infections diseases in the past. But reaching high enough levels of vaccination coverage to attain herd immunity is often a challenge. So, while several safe and effective vaccines against COVID-19 are currently available, some 30% of Americans are hesitant or reticent, as in […]