... That's literally the first line of the article. Handy tip: When the article provides its source material and even links to it, it doesn't really matter whe

... That's literally the first line of the article. Handy tip: When the article provides its source material and even links to it, it doesn't really matter whether you heard of it before or not. On top of that: "Meanwhile, the European Medicines Agency (EMA) cautioned last week that there was no evidence to back a fourth booster, warning that repeat boosters every four months might actually weaken people’s immune systems". The source for that is also linked in the article.