The COVID-19 pandemic continues to weigh heavily on our public health systems. Mass vaccination is one of the major factors in in helping to slow or halt the epidemic. However, in many countries, the supply of vaccines is a problem. The gap between 2 doses has had to be increased in order to be able […]

Acquiring effective immunity is a key element in our fight against the virus. Good immunity gives robust and durable protection. However, there are two types of adaptive immunity against SARS-CoV-2: the first is natural immunity, acquired when infection with the virus takes place, and the other is vaccinal immunity. Their effect may even be cumulative. […]

The COVID-19 pandemic remains a major problem for public health. It has infected more than 200 million people and there have been more than 4,3 million deaths. Post SARS-CoV-2 infection after-effects have already been reported, and this is becoming a matter for concern in view of the large number of cases. Until recently, 2 studies […]

By March 2021, some African countries had suffered two waves of infection with a total of more than 2,9 million people affected and more than 74 000 deaths. As is the case in other parts of the world, the effects of the pandemic are extremely variable from one country to another. These variations may be […]

For a century now, scientists have believed that the main means of respiratory virus transmission is through droplets released by coughing or sneezing, which are deposited on the mucus membranes (eyes, nose or mouth) of a potential new host, or on a surface via which they can infect. These droplets can travel more than 1 […]

SARS-CoV-2 has numerous similarities with endemic human coronaviruses (HCoV), which cause common infections. Several studies suggest that anti-HCoV immunity exists, capable of combatting SARS-CoV-2, although its role in the physiopathology of COVID-19 is unclear. This cross-immunity is hotly debated, but in the light of its importance for vaccination, it is crucial to better understand its […]

Since the first cases of COVID-19 in December 2019 in Wuhan, we have been trying to establish the origins of SARS-CoV-2. Currently, several hypotheses are being debated.    Firstly, did SARS-CoV-2 emerge from an animal reservoir (zoonosis)? A large majority of human viruses do, in effect, emerge from animal sources. Coronaviruses infect numerous species, including humans, […]

The United States was the country with the highest numbers of COVID-19  cases and deaths in the world in 2020. 3 waves of the epidemic followed in quick succession: the 1st in the springtime, after the virus first appeared in the country, affecting mainly urban areas; the 2nd during the summer, affecting mainly the south […]

SARS-CoV-2 is a member of the genus β-coronavirus and subgenus sarbecovirus. Other sarbecoviruses have already caused epidemics, such as SARS-CoV in 2003 (about 8 000 infections and 800 deaths) and MERS-CoV in 2012 (at least 2 600 cases and 900 deaths). Sarbecoviruses have spike surface proteins, the target of powerful neutralising antibodies, that differ while […]

Obtaining a vaccine that works against COVID-19 has been one of the main priorities of recent times. Numerous candidate vaccines, using different technological platforms, have been developed. These vaccines, designed by expressing the SARS-CoV-2 spike surface protein, induce neutralising antibodies against this virus. However, the emergence of variants such as Alpha or Delta, that have […]