The delta variant is now dominant in several territories, notably in the United States and in France. Although messenger RNA vaccines against Covid-19 protect populations against severe forms of the disease, their effectiveness is being revised downwards, according to a study published by the Centers for Disease Control and Prevention (CDC).
Efficiency increased from 91 to 66%
The delta variant, which is more transmissible, seems to have some consequences on the level of efficacy of Moderna and Pfizer vaccines. According to the results of a scientific study carried out in the United States by the CDC, the protection conferred by the sera decreased, as it decreased from approximately 66% compared to 91% initially, since the emergence of the variant. delta. Thousands of professionals working in health centers and hospital wards across six states have been screened weekly to identify possible infection. Note that most of the nursing staff received the two RNA vaccines.
However, this moderate decrease in vaccine efficacy may not be solely related to the delta variant. It is possible, according to the authors of the study, that it is also the weather which could be the cause. In addition, it is necessary to continue the investigations in order to collect data in the long term.
Vaccination remains a key step in the fight against the epidemic
Even if the immunity provided by vaccines can erode over time, it still remains high, especially against severe forms that may induce admission to intensive care. Also, vaccination remains essential to contain the coronavirus epidemic. Indeed, according to the first American public health agency, “ While these interim data suggest a moderate reduction in the effectiveness of Covid-19 vaccines in preventing infection, the fact that the reduction in infections remains at two-thirds underscores the continued importance and benefit of vaccination. ”
However, the US health authorities still want to set up a recall campaign from mid-September. This is also the case in France, because the High Authority of Health recommended on August 24 to administer a booster dose to people aged 65 and over and to the most vulnerable.
