A fourth dose of the Pfizer/BioNTech vaccine lowered Covid-19 rates in the elderly, but protection against infection appeared short-lived, a large study in Israel has found.
The second booster’s protection against infection declined after four weeks, Israeli researchers showed in their study published Tuesday in the New England Journal of Medicine.
Protection against severe disease did not decline in the six weeks following dosing, but additional follow-up studies were needed to assess its longer-term protection, the researchers said.
The study of 1.3 million people aged 60 and over looked at data from the Israeli Ministry of Health database between January 10 and March 2, when the Omicron variant was predominant.
It comes ahead of a meeting of the United States Food and Drug Administration on Wednesday to discuss the need for additional boosters, a week after the United States authorized a second booster shot for people aged 50 and over in the middle from a propagation of the Omicron BA .2 subvariant.
EU health ministers have also urged governments across the bloc to support a fourth dose for people over 60.
In Asia, South Korea began distributing fourth doses of Covid-19 vaccines in February and Singapore said a second booster dose was planned for people aged 80 and over.
Another Israeli study showed last month that elderly people who received a second booster of the Pfizer Inc/BioNTech SE Covid-19 vaccine had a 78% lower mortality rate than those who received just one. .
Israel began offering a second booster in January.
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