Mutations of SARS-CoV-2 occur at an average of 1-2 per month. The majority of these mutations are not worrying, but some of them can have serious consequences. They may, for example, make the virus more easily transmissible or give it greater capacity to evade immunity conferred by vaccination. The first variant giving cause for concern […]

Several effective and safe vaccines against SARS-CoV-2 are now on the market. They were developed in record time, and are based specifically on inhibiting the virus’ spike (S) surface protein. The S protein, and more particularly the RBD region, binds to the ACE2 region to enable entry of the viral particle into the cell. This […]

The SARS-CoV-2 spike protein enables the entry of the virus into the cell. Its RBD (receptor binding domain) is the principal target of neutralizing antibodies that block this mechanism. British and African researchers (at University College London, CITIID Cambridge, and AHRI Durban) studied the evolution of this protein in a man in his seventies, immunocompromised, […]

In the early stages of infection by SARS-CoV-2 we mainly develop antibodies targeting the N protein (nucleocapsid, responsible for organisation of the viral genome) and the S protein (spike, responsible for the binding of the virus to the cell). Some of these are neutralizing, meaning that they target the spike and block its interaction with […]

The duration of immune memory after SARS-CoV-2 infection remains uncertain. Since this virus emerged only recently, there are no existing studies on long-term immunity. Immune memory comes from  B lymphocytes and T lymphocytes  (memory B and T cells) and antibodies specifically directed against the pathogen. Effective long-term protection does not necessarily involve a strong response […]

Amongst the treatments used against COVID-19 are those using therapeutic antibodies. Similar methods used against other viruses have proved ineffective due to mutations in the regions targeted by the antibodies. These mutations may have been caused by selective pressure in a patient during treatment or in an individual infected by a variant which has emerged […]

Worldwide molecular studies have identified 330 000 SARS-CoV-2  viral sequences which have been collected and shared via the GISAID Initiative (ww.gisaid.org). This data is essential to observe the evolution of the pandemic and the emergence of new variants. Mutations appear within the spike protein, which interacts with the ACE2 cellular receptor to enable the virus to […]

Although vaccines against SARS-CoV-2 do exist, they cannot fully protect immunocompromised patients for example. Other prophylaxes or therapeutics need to be developed for high-risk patients. Therapeutic neutralizing antibodies may provide an alternative. However, they are complicated and costly to produce. In addition, these “conventional” antibodies may, in certain cases, facilitate infection as previously described for […]

COVID-19 takes on different forms depending on the patient, from asymptomatic to very severe cases. The majority of patients do, however, manifest moderate symptoms. In patients with severe symptoms, a huge immune response occurs, notably involving neutrophil polynuclear cells, monocytes and platelets, but this  response seems to be ineffective. The causes and consequences of these […]

2 vaccines and 2 treatments based on antibodies have been authorised in the United States against COVID-19. However, the question remains as to whether they will be effective against new variants of the virus. In addition, epidemics are recurrent, and there are numerous coronaviruses active in the animal reservoir which may, like SARS-CoV-2, cross the […]