Looking at the same data from Israel, the U.S. Food and Drug Administration announced last week that Americans aged 50 and older and some others could receive a second booster four months after their first booster shoots. The U.S. Centers for Disease Control and Prevention also encouraged second boosters for those groups.
Europe is coming out of a surge of new coronavirus cases accelerated by the Omicron subvariant known as BA.2.
“There is no clear evidence at the moment that vaccine protection against severe disease is waning substantially in adults between 60 and 79 years of age with a normal immune system, to support the need of a fourth dose,” Andrea Ammon, the E.C.D.C. director, said in a video statement.
“Nevertheless, national authorities should closely monitor the population experiencing severe Covid-19, and decide to use a fourth dose if there are signals of increasing risk among those who already received the third dose,” she said, referring to the 60-to-79 age group.
For healthy adults younger than 60, there was yet “no indication” that an additional booster dose would be of value, Ms. Ammon added. The agencies said they would continue to review evidence and update recommendations as necessary.