... die Datengrundlage sei für die Empfehlung mehrerer booster pro Jahr nicht ausreichend...
Not enough data to support multiple annual COVID boosters, U.S. CDC advisers say | Reuters
There is not sufficient evidence to recommend more than one COVID-19 booster shot a year for older people and those with weakened immune systems, an expert advisory group to the U.S. Centers for Disease Control and Prevention (CDC) said on Friday.