Pfizer and BioNTech said on March 15 that they have applied to the U.S. Food and Drug Administration for approval of an additional booster dose of their COVID-19 vaccine for people 65 years and older. The request was based on data from Israel analyzed at the time the Omicron variant was circulating widely, the alliance of U.S. and German companies said in a statement. These data show, according to Pfizer and BioNTech, that "an additional booster dose of messenger RNA vaccine increases immunogenicity" - the ability to elicit an immune response - "and reduces rates of confirmed infection and severe disease." As a result, the two pharmaceutical companies have applied for emergency use approval from the FDA, the US drug agency. Israel was the first country to launch a new vaccine campaign. The fourth dose of Pfizer's anti-COVID vaccine has been administered since the beginning of January to people over 60 years of age and was extended at the end of January to those over 18 years of age who are at risk. It increases antibodies three to five times compared to the third dose, according to the Israeli Ministry of Health. A second booster dose (often the fourth dose of vaccine) targeted at the oldest and/or most vulnerable people is, since then, on the agenda in several European countries: Denmark, Spain, Germany, Sweden.